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Dahoas

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base_code_review

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<p>As an exercise, I have implemented a circular bounded queue using arrays as the base data structure. I'd appreciate it if someone can review it for me.</p> <pre><code> class BoundedQueue&lt;T&gt; { T[] que; int head; // remove from head int tail; // insert at tail public BoundedQueue(int quesize) { head = tail = -1; que = new T[quesize]; } public void enqueue(T elem) // if next index to tail == head =&gt; Q is FULL { int newIndex = nextIndex(tail); if ( newIndex == head) throw new BoundedQueueException(Full); tail = newIndex; que[newIndex] = elem; if (head == -1) head = 0; } public T dequeue() // After removing from head, if that was the only element in Q // Mark Q to be empty by setting head and tail to -1 { if (head == -1) throw new BoundedQueueException(Empty); T elem = que[head]; que[head] = default(T); if (head == tail) { head = tail = -1; } else { head = nextIndex(head); } return elem; } private int nextIndex(int index) { return (index + 1) % que.Length; } } </code></pre>

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<p>This Common Lisp program is an exercise to print an integer and its digits reversed to the screen:</p> <pre><code>(defun read-number () (format t "Enter a number: ~%") (read)) (defun reverse-string (the-string) (if (eq (length the-string) 0) "" (concatenate 'string (reverse-string (subseq the-string 1)) (subseq the-string 0 1)))) (defun reverse-digits (the-number) (reverse-string (write-to-string the-number))) (let ((the-number (read-number))) (format t "N-&gt;: ~a~%&lt;-N: ~a~%" the-number (reverse-digits the-number))) </code></pre>

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<p>I need to place a Google map in Colorbox overlay and am wondering if there's a better way to do this. I've just started out with Google's tutorial so there's nothing fancy going on.</p> <p>Right now I'm hiding the div that Google loads the map into:</p> <pre><code>&lt;div style="width:0; height: 0; overflow: hidden;"&gt; &lt;div id="map_canvas" style="width:600px; height:400px; "&gt;&lt;/div&gt; &lt;/div&gt; </code></pre> <p>Here's the call to Colorbox:</p> <pre><code>var latlng = new google.maps.LatLng(-34.397, 150.644); var myOptions = { zoom: 8, center: latlng, mapTypeId: google.maps.MapTypeId.ROADMAP }; var map = new google.maps.Map(document.getElementById("map_canvas"), myOptions); $(document).ready(function(){ $("#farm_on_google_maps").colorbox({ inline: true, width:700, height:450, href : '#map_canvas' }); }); </code></pre> <p>Even though it works, I wonder if the map could be loaded directly into Colorbox.</p>

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<p>I have two helper methods that return li for view with the li for current view having id as selected. </p> <pre><code>def get_li(a) li = "&lt;li" li += ' id=selected' if (a[:controller] == params[:controller] &amp;&amp; a[:action] == params[:action]) li += "&gt;" + link_to(a[:text], { :controller =&gt; a[:controller], :action =&gt; a[:action]}) + "&lt;/li&gt;" end def get_tab_options if (params[:controller] == 'sessions' || params[:controller] == 'users') [{:text =&gt; "Login", :controller =&gt; 'sessions', :action =&gt; 'new'}, {:text =&gt; "Sign Up", :controller =&gt; 'users', :action =&gt; 'new'}] elsif (params[:controller] == 'meetings') [{:text =&gt; "Meetings List", :controller =&gt; 'meetings', :action =&gt; 'index'}, {:text =&gt; "Create Meeting", :controller =&gt; 'meetings', :action =&gt; 'new'}, {:text =&gt; "Running Meetings", :controller =&gt; 'meetings', :action =&gt; 'monitor'}] end end </code></pre> <p>And the view file has</p> <pre><code> %ul -get_tab_options.each do |a| = get_li(a) </code></pre> <p>How can I write this better?</p>

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<p>I needed a function that would take a list of folders and removed all sub folders, so that only the top level folders stayed in the list. </p> <p>For example, given the list:</p> <pre><code>c:\stuf\morestuff c:\stuf\morestuff\sub1 c:\otherstuf c:\otherstuf\sub1 c:\otherstuf\sub2 </code></pre> <p>I wanted the list to be reduced to:</p> <pre><code>c:\stuf\morestuff c:\otherstuf </code></pre> <p>So I came up with this solution:</p> <pre><code>// remove empty strings and sub folders private static void CleanUpFolders(List&lt;string&gt; uniqueFolders) { uniqueFolders.RemoveAll( delegate(string curFolder) { // remove empty if (string.IsNullOrEmpty(curFolder)) return true; // remove sub paths if (uniqueFolders.Exists( delegate(string s) { if (!string.IsNullOrEmpty(s) &amp;&amp; curFolder.StartsWith(s) &amp;&amp; string.Compare(s, curFolder) != 0) return true; return false; } )) return true; return false; } ); } </code></pre> <p>This seems to work (not very well tested though) but I was left wondering about some things:</p> <ul> <li>is there an issue with using variables inside anonymous methods that were declared outside?</li> <li>any potential issues with nested anonymous methods?</li> <li>any other issues or best practices worth mentioning?</li> </ul>

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<p>This code is intended to find all possible solutions to a cryptoarithmetic problem. The description of the problem I was trying to solve is here:</p> <blockquote> <p>In cryptoarithmetic problems, we are given a problem wherein the digits are replaced with characters representing digits. A solution to such a problem is a set of digits that, when substituted in the problem, gives a true numerical interpretation.</p> <p>Example:</p> <pre><code>IS IT ___ OK </code></pre> <p>has a solution</p> <pre><code>{ I = 1; K = 1; O = 3; S = 5; T = 6} </code></pre> <p>For each of the below cryptoarithmetic problems, write a program that finds all the solutions in the shortest possible time.</p> <pre><code>IS I IT AM __ __ OK OK </code></pre> </blockquote> <p>I was only able to solve it using brute force, though I believe there are more efficient methods. I am also hoping to receive feedback on my formatting, naming, and really anything you think could use improvement.</p> <pre><code>(defun place-value-to-integer (the-list &amp;OPTIONAL place-value) (let ((place-value (if place-value place-value 1))) (if (= (length the-list) 1) (* place-value (first the-list)) (+ (* place-value (first (last the-list))) (place-value-to-integer (butlast the-list) (* 10 place-value)))))) (defun fill-from-formula (formula guess) (loop for digit in formula collect (gethash digit guess))) (defun check-answer (augend-formula addend-formula sum-formula guess) (let ((augend (fill-from-formula augend-formula guess)) (addend (fill-from-formula addend-formula guess)) (sum (fill-from-formula sum-formula guess))) (= (place-value-to-integer sum) (+ (place-value-to-integer augend) (place-value-to-integer addend))))) (defun brute-force-guess(augend-formula addend-formula sum-formula unique-values &amp;OPTIONAL callback guess) (let ((guess (if (null guess) (make-hash-table) guess))) (loop for digit in '(0 1 2 3 4 5 6 7 8 9) do (setf (gethash (car unique-values) guess) digit) (if (= (length unique-values) 1) (if (check-answer augend-formula addend-formula sum-formula guess) (print-result augend-formula addend-formula sum-formula guess) nil) (brute-force-guess augend-formula addend-formula sum-formula (cdr unique-values) callback guess))))) (defun print-result (augend-formula addend-formula sum-formula guess) (format t "One answer is ~a + ~a = ~a ~%" (fill-from-formula augend-formula guess) (fill-from-formula addend-formula guess) (fill-from-formula sum-formula guess))) (defun find-unique-values (the-list) (let ((unique-items ())) (loop for sublist in the-list do (loop for item in sublist do (unless (member item unique-items) (setf unique-items (append (list item) unique-items))))) unique-items)) (let ((problemA (list (list 'I 'S) (list 'I 'T) (list 'O 'K))) (problemB (list (list 'I) (list 'A 'M) (list 'O 'K)))) (brute-force-guess (first problemA) (second problemA) (third problemA) (find-unique-values problemA) #'print-result) (brute-force-guess (first problemB) (second problemB) (third problemB) (find-unique-values problemB) #'print-result)) </code></pre>

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<p>I saw a sassy CSS for a rails app like this:</p> <pre><code>$std-margin: 30px; @mixin solid-bg($color: #EEEEEE) { background: none repeat scroll 0 0 $color; } @mixin solid-border($direction, $width: 1px, $color: black) { @if $direction == "" { border: { color: $color ; width: $width; style: solid; } } @else { border-#{$direction}: { color: $color ; width: $width; style: solid; } } } html { font: 90%/1.3 arial,sans-serif; body { margin: $std-margin; .top-nav { text-align: center; width: 100%; .login { float: right; padding-right: 63px; clear: both; } a { text-decoration: none; } } .content { @include solid-border(""); clear: both; padding: 15px; } h2 { margin: $std-margin; margin-left: 0px; } h3, .detail { margin: $std-margin; } #header { ul { list-style: none outside none; padding: 0; li { float: left; a { @include solid-bg(); color: #0000CC; display: block; padding: 0.24em 1em; text-decoration: none; } } } #selected a { @include solid-bg(white); color: black; font-weight: bold; position: relative; top: 1px; @include solid-border(""); @include solid-border('bottom', 0px); } } label { float: left; margin-right: 1em; text-align: right; width: 10em; } input { @include solid-bg(#FAFAFA); -moz-border-radius: 0.4em 0.4em 0.4em 0.4em; @include solid-border("", 1px, #DDDDDD); font: bold 0.95em arial,sans-serif; padding: 0.15em; width: 10em; } .field { padding: 5px; clear: both; input { width:12em; @include solid-border("", 1px, #006); @include solid-bg(#ffc); &amp;:hover { @include solid-border(""); @include solid-bg(#ff6); } } .fieldWithErrors { float: left; padding: 3px; input { @extend .field.input; @include solid-border("", 2px, red); } } .create { width:5em; } .submit { @include solid-bg(#D0DAFD); border: 0 none; cursor: pointer !important; display: block; height: 26px; margin: 1em; overflow: hidden; width: 69px; } } table { border-collapse: collapse; margin: 20px; text-align: left; width: 480px; font { family: "Lucida Sans Unicode","Lucida Grande",Sans-Serif; size: 12px; } th { @include solid-bg(#B9C9FE); @include solid-border('bottom', 1px, #FFFFFF); @include solid-border('top', 4px, #AABCFE); color: #003399; font-size: 13px; font-weight: normal; padding: 8px; } tr { @include solid-bg(#E8EDFF); &amp;:hover td { @include solid-bg(#D0DAFD); color: #333399; } td.title { color: #333399; } } td { @include solid-border('bottom', 1px, #FFFFFF); @include solid-border('top', 1px, transparent); color: #666699; padding: 8px; } } .activities { padding: 10px; a{ margin: 10px; } } .flash { font-family:'Trebuchet MS'; color:#FF0000; font-size:14px; } .calendar_date_select table { width: 78px; td { padding: 5px; } } .main-content { clear: both; float: left; width: 100%; } .clear { clear: both; } #errorExplanation { @include solid-bg(); margin: 10px; padding: 5px 0 5px 20px; } } } </code></pre> <p>Using best practice how this can be optimized?</p>

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<p>I have this code in a class sharing a private static array of data. Internally it's encoded, but I need the iterator for a <code>foreach</code> loop to show the decoded values.</p> <p>Is there a native array function that can remap the keys and values via a callback function?</p> <pre><code>public function getIterator( ) { $arr = array(); foreach ( self::$data as $encName =&gt; $encValue ) { $name = $this-&gt;decode( $encName ); $value = $this-&gt;decode( $encValue ); $arr[$name] = $value; } return new ArrayIterator( $arr ); } </code></pre>

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<p>I have a function that takes in a controller instance, a method, and parameters (this is for a little MVC experiment I'm working on). The purpose of the function is to execute the controller method with the given parameters.</p> <p>However, there are a few caveats. First, if the controller has a "router" method, it will call that instead of the method that was passed in. Second, if any of the controller "annotations" return a response, that will also override the method. Then, if those cases fail, we return the response of the actual controller method passed in.</p> <p>It looks like this:</p> <pre><code> switch (true) { // Router methods get first priority! case ($controller-&gt;using_router): $response = call_user_func_array(array($controller, 'router')); break; // Annotation responses take precedence over method responses because they are often used for authentication. case ( ! is_null($response = Annotation\Runner::run(Annotation\Extractor::extract($controller, $method)))): break; // No router or annotation responses... we're ready to run the method! default: $response = call_user_func_array(array($controller, $method), $parameters); } </code></pre> <p>For some reason, this just feels dirty. I don't like the <code>break</code> after checking for an annotation response. But, I'm not sure of any other way to implement a response "priority".</p> <p>Is there a better way?</p>

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<p>I am locating the find method of List in C# with the single Expression type parameter</p> <p>I am using the following ( where T is a List, in my case a SubSonic IActiveRecord )</p> <pre><code>MethodInfo info = typeof(T).GetMethods(BindingFlags.Static | BindingFlags.Public) .FirstOrDefault(m =&gt; m.Name == "Find" &amp;&amp; m.GetParameters().Count() == 1); </code></pre> <p>This works perfectly well, but feels clunky (especially the parameter count part) and I'm not sure how future proof it is.</p>

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<p>I would like to have my code reviewed, I'm trying to get a general model I'm using for my stuff going and I don't want to keep using wrong or inefficient code if I can.</p> <p>My file structure is like this: </p> <p><img src="https://i.stack.imgur.com/0equs.png" alt="File structure"></p> <p>In conf there's a file sitting called database.conf.php with the following content: </p> <pre><code>&lt;?php $this-&gt;host = "localhost"; $this-&gt;user = "snowclouds_LoL"; $this-&gt;password = "****"; $this-&gt;database = "snowclouds_LoL"; ?&gt; </code></pre> <p>In functions I have my functions included like this in functions.php</p> <pre><code>&lt;?php //Constructor class for calling all function scripts. require("database.php"); require("security.php"); require("show.php"); require("user.php"); require("misc.php"); ?&gt; </code></pre> <p>This is my database class:</p> <pre><code>&lt;?php class Database { private $host; private $user; private $password; private $database; private $link; public function connect(){ $this-&gt;link = mysqli_connect ($this-&gt;host, $this-&gt;user, $this-&gt;password) or die("Connection problem: " . mysqli_error()); mysqli_select_db($this-&gt;link, $this-&gt;database); } public function resultquery($query){ $result = mysqli_query($this-&gt;link, $query) or die(mysqli_error($this-&gt;link)); return $result; } public function insertquery($query){ if(mysqli_query($this-&gt;link, $query)){ return true; }else{ return mysqli_error($this-&gt;link); } } public function __construct(){ if(!file_exists("conf/database.conf.php")){ die("conf/database.conf.php file does not exist!"); }else{ include('conf/database.conf.php'); } } } ?&gt; </code></pre> <p>Indenting is a little broke because pasting 4 spaces before every line is just time consuming :/</p> <p>This is my index.php <pre><code>$show-&gt;header(); $show-&gt;menu(); require("act.php"); $show-&gt;footer(); ?&gt; </code></pre> <p>This is my init.php</p> <pre><code>&lt;?php session_start(); ob_start(); require ("functions/functions.php"); //Check security for hackers. $security = new Security(); $security-&gt;checkuri(); $user = new User(); $misc = new Misc(); $show = new Show(); ?&gt; </code></pre> <p>And in my act.php I write code like this:</p> <pre><code>if(isset($_GET['act']) &amp; $_GET['act'] == "lostpass"){ if(isset($_SESSION['username'])){ $show-&gt;error("U bent al ingelogd met een bestaand account en u kunt uw wachtoowrd dus gewoon aanpassen op de aanpas pagina."); }else{ include("view/lostpass.php"); } } </code></pre> <p>The files in view contain mostly html code with an occasional while for tables.</p> <p>So how is this structure? </p> <p>Is it good or unbelievably bad? (I want to stay away from stuff like Smarty because I want my own model for this kind of stuff and I'm still learning).</p> <p>Extra stuff: </p> <p>This is my Misc class: </p> <pre><code>&lt;?php class Misc{ function check_email($email) { // First, we check that there's one @ symbol, // and that the lengths are right. if (!ereg("^[^@]{1,64}@[^@]{1,255}$", $email)) { // Email invalid because wrong number of characters // in one section or wrong number of @ symbols. return false; } // Split it into sections to make life easier $email_array = explode("@", $email); $local_array = explode(".", $email_array[0]); for ($i = 0; $i &lt; sizeof($local_array); $i++) { if (!ereg("^(([A-Za-z0-9!#$%&amp;'*+/=?^_`{|}~-][A-Za-z0-9!#$%&amp; ?'*+/=?^_`{|}~\.-]{0,63})|(\"[^(\\|\")]{0,62}\"))$", $local_array[$i])) { return false; } } // Check if domain is IP. If not, // it should be valid domain name if (!ereg("^\[?[0-9\.]+\]?$", $email_array[1])) { $domain_array = explode(".", $email_array[1]); if (sizeof($domain_array) &lt; 2) { return false; // Not enough parts to domain } for ($i = 0; $i &lt; sizeof($domain_array); $i++) { if (!ereg("^(([A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9])| ?([A-Za-z0-9]+))$", $domain_array[$i])) { return false; } } } return true; } } ?&gt; </code></pre> <p>It's just for stuff that's pretty annoying to fully put into everything each time I need it.</p> <p>Security: </p> <pre><code>&lt;?php /** * @author Jeffro * @copyright 2011 */ class Security{ var $privatekey = "thisshouldgoinaconfigfileaswell"; function mcryptexists() { if (function_exists("mcrypt_encrypt")){ return true; }else{ return false; } } function sslactive() { if ($_SERVER['HTTPS']) { return true; }else{ return false; } } function safe_b64encode($string) { $data = base64_encode($string); $data = str_replace(array('+','/','='),array('-','_',''),$data); return $data; } function safe_b64decode($string) { $data = str_replace(array('-','_'),array('+','/'),$string); $mod4 = strlen($data) % 4; if ($mod4) { $data .= substr('====', $mod4); } return base64_decode($data); } function encode($value){ if(!$value){return false;} $text = $value; $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB); $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND); $crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $this-&gt;privatekey, $text, MCRYPT_MODE_ECB, $iv); return trim($this-&gt;safe_b64encode($crypttext)); } function decode($value){ if(!$value){return false;} $crypttext = $this-&gt;safe_b64decode($value); $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB); $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND); $decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $this-&gt;privatekey, $crypttext, MCRYPT_MODE_ECB, $iv); return trim($decrypttext); } } ?&gt; </code></pre> <p>That's from my new project btw. (Plesk API system)</p> <p>And here is my show class:</p> <pre><code> &lt;?php class show{ function header(){ include("view/header.php"); } function menu(){ include("view/menu.php"); } function footer(){ include("view/footer.php"); } function error($message){ echo $message; $this-&gt;footer(); die(); } } ?&gt; User Class: &lt;?php class User{ private $database; function exists($user){ $this-&gt;database-&gt;connect(); if($result = $this-&gt;database-&gt;resultquery("SELECT * FROM users WHERE got_username='" . $user . "'")) { $count = mysqli_num_rows($result); if($count &gt; 0){ return true; }else{ return false; } } } function isfriend($user, $friend){ $this-&gt;database-&gt;connect(); if($result = $this-&gt;database-&gt;resultquery("SELECT * FROM friends INNER JOIN users ON friends.user_id = users.user_id WHERE users.got_username='" . $user . "' AND friends.friend_id='" . $friend . "'")) { $count = mysqli_num_rows($result); if($count &gt; 0){ return true; }else{ return false; } } } function addfriend($username, $friend){ $this-&gt;database-&gt;connect(); $user = $this-&gt;getuser($username); $result = $this-&gt;database-&gt;insertquery("INSERT INTO friends (user_id, friend_id) VALUES ('" . $user['user_id'] . "', '" . $friend . "')"); return $result; } function delfriend($username, $friend){ $this-&gt;database-&gt;connect(); $user = $this-&gt;getuser($username); $result = $this-&gt;database-&gt;insertquery("DELETE FROM friends WHERE user_id = '" . $user['user_id'] . "' AND friend_id = '" . $friend . "'"); return $result; } function updateuser($got_username, $eu_username, $us_username, $user_client, $play_ranked, $user_email, $user_password, $user_password_check, $comment, $ip, $date){ $this-&gt;database-&gt;connect(); $result = $this-&gt;database-&gt;insertquery(" UPDATE users SET EU_username='$eu_username', US_username='$us_username', user_client='$user_client', plays_ranked='$play_ranked', comment='$comment', user_email='$user_email', user_password='" . sha1($user_password) . "', last_login='$date', last_ip='$ip' WHERE GoT_username='$got_username'"); return $result; } function updateusernopass($got_username, $eu_username, $us_username, $user_client, $play_ranked, $user_email, $comment, $ip, $date){ $this-&gt;database-&gt;connect(); $result = $this-&gt;database-&gt;insertquery(" UPDATE users SET EU_username='$eu_username', US_username='$us_username', user_client='$user_client', plays_ranked='$play_ranked', comment='$comment', user_email='$user_email', last_login='$date', last_ip='$ip' WHERE GoT_username='$got_username'"); return $result; } function register($got_username, $eu_username, $us_username, $user_client, $play_ranked, $user_email, $user_password, $user_password_check, $comment, $ip, $date){ $result = $this-&gt;database-&gt;insertquery(" INSERT INTO users (GoT_username, EU_username, US_username, user_client, plays_ranked, comment, user_email, user_password, reg_date, last_login, last_ip) VALUES ('$got_username', '$eu_username', '$us_username', '$user_client', '$play_ranked', '$comment', '$user_email', '". sha1($user_password) ."', '$date', '$date', '$ip')"); return $result; } function getusers(){ $this-&gt;database-&gt;connect(); $query = "SELECT * FROM users ORDER BY user_id DESC"; $result = $this-&gt;database-&gt;resultquery($query); $array = array(); while($value = mysqli_fetch_array($result)) { $array[] = $value; } return $array; } function inserthash($email, $hash){ $this-&gt;database-&gt;connect(); $query = "UPDATE users SET user_hash='$hash' WHERE user_email='$email'"; $result = $this-&gt;database-&gt;insertquery($query); return $result; } function updatepassword($hash, $password){ $this-&gt;database-&gt;connect(); $password = sha1($password); $query = "UPDATE users SET user_password='$password' WHERE user_hash='$hash'"; $this-&gt;database-&gt;insertquery("UPDATE users SET user_hash='' WHERE user_hash='$hash'"); $result = $this-&gt;database-&gt;insertquery($query); return $result; } function existsbyemail($email){ $this-&gt;database-&gt;connect(); $query = "SELECT * FROM users WHERE user_email = '$email'"; $result = $this-&gt;database-&gt;resultquery($query); $count = mysqli_num_rows($result); if($count &gt; 0){ return true; }else{ return false; } } function getuserbyemail($email){ $this-&gt;database-&gt;connect(); $query = "SELECT * FROM users WHERE user_email = '$email'"; $result = $this-&gt;database-&gt;resultquery($query); $array = mysqli_fetch_array($result); return $array; } function getuser($username){ $this-&gt;database-&gt;connect(); $query = "SELECT * FROM users WHERE GoT_username = '$username'"; $result = $this-&gt;database-&gt;resultquery($query); $array = mysqli_fetch_array($result); return $array; } function login($username, $password){ $this-&gt;database-&gt;connect(); $query = "SELECT * FROM users WHERE GoT_username = '$username' AND user_password = '". sha1($password) . "'"; $result = $this-&gt;database-&gt;resultquery($query); $count = mysqli_num_rows($result); if($count &gt; 0){ return true; }else{ return false; } } function logout(){ unset($_SESSION['GoT_username']); unset($_SESSION['users_password']); } public function __construct(){ $this-&gt;database = new Database(); } } ?&gt; </code></pre>

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<p>I need to subclass <code>UIButton</code>, however the design of <code>UIButton</code> makes this really painful. This is because to create a button you really need to call:</p> <pre><code>[UIButton buttonWithType:UIButtonTypeRoundedRect] </code></pre> <p>So if I want to subclass I really need to do whatever it is this method does. However, it is not possible to set the buttons underlying type.</p> <p>One option is to use something like decorator and subclass <code>UIButton</code> but have the actual button as an ivar and defer all property/method calls to this button. The problem here is that I then need to implement most of the <code>UIButton</code> interface (yawn).</p> <p>What I have done is something a bit sneakier in my sub class. I have created this method:</p> <pre><code>- (id) initWithType:(UIButtonType)buttonType { [super init]; actualButton = [[UIButton buttonWithType:buttonType] retain]; memcpy(self, actualButton, sizeof(UIButton)); self-&gt;isa = [ABDescriptorButton class]; return self ; } </code></pre> <p>I know this is pretty unorthodox, but it works and is fairly clean in terms of code. What are the pitfalls I might have with this approach? </p>

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<p>I'm making a simple container class for fun and education, but my rebuilding/resizing method seems rather inefficient. Is there an easier way to do this?</p> <pre><code>// If FromFront is true, cells should be added or // subtracted from the front of the array rather than the back. void Rebuild(std::size_t NewSize, bool FromFront = false) { const std::size_t OldSize = Size; Size = NewSize; // Size is used in other methods. Datatype* TemporaryStorage = new Datatype[OldSize]; // Allocate space for the values to be preserved while a new main array is made. for (std::size_t Index = 0; Index &lt; OldSize; Index++) TemporaryStorage[Index] = BasePointer[Index]; // Copy values over to the temporary array. delete[] BasePointer; // Delete the main array... BasePointer = new Datatype[NewSize]; // ...And rebuild it with the appropriate size. for (std::size_t Iteration = 0; (Iteration &lt; OldSize) &amp;&amp; (Iteration &lt; NewSize); Iteration++) { std::size_t BasePointerIndex = Iteration; std::size_t TemporaryStorageIndex = Iteration; if (FromFront) // We need to take special measures to give the indices offsets. { if (NewSize &gt; OldSize) BasePointerIndex += (NewSize - OldSize); else TemporaryStorageIndex += (OldSize - NewSize); } BasePointer[BasePointerIndex] = TemporaryStorage[TemporaryStorageIndex]; // Copy values from the temporary array to the new main array. } delete[] TemporaryStorage; // Finally, delete the temporary storage array. } </code></pre>

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<pre><code>#include&lt;stdafx.h&gt; #include&lt;stdio.h&gt; #include&lt;stdlib.h&gt; #include&lt;string&gt; #include&lt;iostream&gt; using namespace std; string temp[10]; void extract(char * c) { int ind = 0; //char *temp = (char *)malloc(sizeof(char)); while(*c!= NULL) { if(*c!= ' ') // read all chars in a word and store in temp. { temp[ind]= temp[ind] + *c; c++; } else if(*c== ' ') // reached end of word { c++; ind++; } } int length = sizeof(temp)/sizeof(temp[0]); printf("The reversed string is"); for(int i=length;i&gt;=0;i--) { cout&lt;&lt;temp[i];// not able to print it with printf statement } } void main() { char *c = "seattle is good"; extract(c); } </code></pre> <p>This should print the sentence in reverse order . Input is "seattle is good" Output for the above will be "good is seattle" I have 2 questions , 1. I am using string array here with size of 10. How can I make it dynamic? 2. For some reason the printf("%s",temp[i]) was not giving me correct results(At the very end of extract method). I then used cout and it was fine. Any ideas why? Am I doing something silly?</p> <p>Algorithm Description: </p> <ul> <li>Take the input string as char array.</li> <li>Extract words from the string by looking for empty space. </li> <li>Store each word in a temp string array. temp[0] = seattle temp[1] = is temp[2] = good</li> <li>Then loop backwards through this temp array and print contents.</li> </ul>

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<p>I have developed an application that interacts with IBM ClearQuest. The problem is that when I run everything locally, such as, run the webservice local and then ASP page local, everything is at the speed I expect. When I post the webservice (precompiled) to the server and run the web page through the server, the call to the webmethod takes at least 10x the amount of time it should. I don't know why this is happening. I made a console application that has the function in question and executes it on the server and locally, and they both return the same amounts of time (roughly). It's just when I move to executing via the webmethod that everything grinds to a snails pace.</p> <p>Any ideas? This happens every time not just on the first call.</p> <p>Maybe a code review might help here?</p> <p><strong>WebMethod (VB):</strong></p> <pre class="lang-vb prettyprint-override"><code>Public Function RetrieveQueryResults(ByRef cqSession As ClearQuestOleServer.Session, _ ByVal sqlStmt As String) As List(Of SearchResultsSingleIssue) Dim numCols As Integer, status As Integer, columnIdx As Integer Dim numRows As Integer Dim rowContents As String = "" Dim colValue As New Object Dim colLabel As New Object Dim allitems As New List(Of SearchResultsSingleIssue) Dim results As New SearchResultsSingleIssue Dim cqResultSet As ClearQuestOleServer.OAdResultset cqResultSet = cqSession.BuildSQLQuery(sqlStmt) cqResultSet.Execute() ' Get the number of columns returned by the query. numRows = 0 numCols = cqResultSet.GetNumberOfColumns status = cqResultSet.MoveNext ' Collect query results. Do While status = AD_SUCCESS results = New SearchResultsSingleIssue numRows = numRows + 1 For columnIdx = 1 To numCols colLabel = cqResultSet.GetColumnLabel(columnIdx) colValue = cqResultSet.GetColumnValue(columnIdx) 'Make sure that we dont pass along a null reference If colValue = Nothing Then colValue = "" End If Select Case colLabel Case "ID" results.IssueID = colValue Case "HEADLINE" results.Headline = colValue Case "NAME" results.State = colValue Case "OE_CONTACT" results.OEContact = colValue Case "DESCRIPTION" results.Further_Description = colValue Case "PRODUCT_NAME" results.Product_Name = colValue Case "FUNCTIONAL_AREA" results.Functional_Area = colValue Case "SUBTOPIC" results.Subtopic = colValue Case "FOUND_VERSION" results.Found_In = colValue Case "SCHEDULED_VERSION" results.Scheduled_For = colValue Case "SYMPTOMS" results.Symptoms = colValue Case "AFFECTED_SYSTEMS" results.Affected_System_Types = colValue Case "ISSUE_TYPE" results.Issue_Type = colValue Case "ASSIGNED_TO" results.Assigned_Developer = colValue Case "TESTED_BY" results.Assigned_Tester = colValue Case "BUILT_VERSION" results.Built_In = colValue Case "TESTED_VERSION" results.Tested_In = colValue Case "NOTES_LOG" results.Notes_Log = colValue Case "CUSTOMER_SEVERITY" results.Severity = colValue Case "PRIORITY" results.Priority = colValue End Select Next columnIdx ' Add the query row result to the compiled list of all rows. allitems.Add(results) status = cqResultSet.MoveNext Loop Return allitems End Function </code></pre> <p><strong>Local Windows Application Method (C#):</strong></p> <pre><code>private void button2_Click(object sender, EventArgs e) { start = DateTime.Now.TimeOfDay.Seconds; int numCols = 0; int status = 0; int columnIdx = 0; int numRows = 0; string rowContents = ""; string colValue; string colLabel; List&lt;SearchResultsSingleIssue&gt; allitems = new List&lt;SearchResultsSingleIssue&gt;(); SearchResultsSingleIssue results = new SearchResultsSingleIssue(); ClearQuestOleServer.OAdResultset cqResultSet = default(ClearQuestOleServer.OAdResultset); cqResultSet = (ClearQuestOleServer.OAdResultset)ClearQuestSession.BuildSQLQuery(sqlStatement); cqResultSet.Execute(); // Get the number of columns returned by the query. numRows = 0; numCols = cqResultSet.GetNumberOfColumns(); status = cqResultSet.MoveNext(); // Collect query results. while (status == 1) { results = new SearchResultsSingleIssue(); numRows = numRows + 1; for (columnIdx = 1; columnIdx &lt;= numCols; columnIdx++) { colLabel = (string)cqResultSet.GetColumnLabel(columnIdx); colValue = (string)cqResultSet.GetColumnValue(columnIdx); //Make sure that we dont pass along a null reference if (colValue == null) { colValue = ""; } switch (colLabel) { case "ID": results.IssueID = colValue; break; case "HEADLINE": results.Headline = colValue; break; case "NAME": results.State = colValue; break; case "OE_CONTACT": results.OEContact = colValue; break; case "DESCRIPTION": results.Further_Description = colValue; break; case "PRODUCT_NAME": results.Product_Name = colValue; break; case "FUNCTIONAL_AREA": results.Functional_Area = colValue; break; case "SUBTOPIC": results.Subtopic = colValue; break; case "FOUND_VERSION": results.Found_In = colValue; break; case "SCHEDULED_VERSION": results.Scheduled_For = colValue; break; case "SYMPTOMS": results.Symptoms = colValue; break; case "AFFECTED_SYSTEMS": results.Affected_System_Types = colValue; break; case "ISSUE_TYPE": results.Issue_Type = colValue; break; case "ASSIGNED_TO": results.Assigned_Developer = colValue; break; case "TESTED_BY": results.Assigned_Tester = colValue; break; case "BUILT_VERSION": results.Built_In = colValue; break; case "TESTED_VERSION": results.Tested_In = colValue; break; case "NOTES_LOG": results.Notes_Log = colValue; break; case "CUSTOMER_SEVERITY": results.Severity = colValue; break; case "PRIORITY": results.Priority = colValue; break; } } // Add the query row result to the compiled list of all rows. allitems.Add(results); status = cqResultSet.MoveNext(); } seconds = (DateTime.Now.TimeOfDay.Seconds - start); label3.Text = seconds.ToString(); } </code></pre> <p>The code executes in about...6 seconds.</p>

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<p>I'm trying to figure out a way to simplify implementing paged searching in sql server.</p> <p>My restrictions are: </p> <ol> <li>has to be in a proc. </li> <li>can't use dynamic sql.</li> </ol> <p>Here's my sample query:</p> <pre><code>DECLARE @TenantId int DECLARE @MemberStatusId int DECLARE @SearchTerm varchar(50) DECLARE @ColumnName varchar(30) DECLARE @PageNum int DECLARE @RecCount int ; WITH RowPages AS ( SELECT TOP( @PageNum * @RecCount ) RowNumber = ROW_NUMBER() OVER( ORDER BY CASE WHEN @ColumnName = 'Name' THEN P.LastName WHEN @ColumnName = 'PhoneNumber' THEN M.PhoneNumber WHEN @ColumnName = '' THEN P.LastName END ASC, CASE WHEN @ColumnName = 'DateAdded' THEN P.DateAdded END DESC ), TotalCount = COUNT(M.MemberId) OVER ( PARTITION BY NULL), M.MemberId, M.ExternalId, M.PhoneNumber, P.FirstName, P.LastName, P.EmailAddress FROM membership.Members M (nolock) INNER JOIN core.Persons P (nolock) on (P.PersonId = M.MemberId) WHERE (M.TenantId = @TenantId) AND ((@MemberStatusId = 0) or (M.MemberStatusId = @MemberStatusId)) AND ( (@SearchTerm = '""') OR (CONTAINS( (P.FirstName, P.LastName, P.EmailAddress), @SearchTerm)) ) ) SELECT TotalCount, MemberId, ExternalId, PhoneNumber, FirstName, LastName, EmailAddress FROM RowPages WHERE RowNumber &gt; ((@PageNum - 1) * @RecCount) ORDER BY RowNumber </code></pre> <p>What this does is perform a paged search of a couple tables. You can pass in the page number and # records per page as well as the column to sort by and it has a full text search component. This is one of the simpler queries of this style we have.</p> <p>What I'm trying to figure out is how to optimize this. The biggest costs in the execution plan are in regards to the full text search. There is a table value function [FullTextMatch] which has a cost of 100%. </p> <p>Ideas?</p>

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<p>What do you think about this code?</p> <pre><code>#include &lt;iostream&gt; using std::cout; using std::endl; #include &lt;vector&gt; using std::vector; #include &lt;ctime&gt; #include &lt;cstdlib&gt; template &lt; typename T &gt; vector &lt; T &gt; concatenate( vector &lt; T &gt; _a_, T piv, vector &lt; T &gt; _b_ ) { vector &lt; T &gt; v_list; v_list.insert( v_list.begin(), _a_.begin(), _a_.end() ); v_list.push_back( piv ); v_list.insert( v_list.end(), _b_.begin(), _b_.end() ); return v_list; } template &lt; typename T &gt; vector&lt; T &gt; quick( vector&lt; T &gt; vec ) { vector&lt; T &gt; v_less, v_greater, v_list; vector&lt; T &gt; aux1, aux2; typename vector &lt; T &gt;::const_iterator iter_Const; if( vec.size() &lt;= 1 ) return vec; int piv = *(vec.end() - 1); vec.pop_back(); for( iter_Const = vec.begin(); iter_Const != vec.end(); ++iter_Const ) { if( *iter_Const &lt; piv ) v_less.push_back( *iter_Const ); else v_greater.push_back( *iter_Const ); } return concatenate( quick( v_less ), piv, quick( v_greater ) ); } int main() { vector &lt; int &gt; lista; srand( 1 ); cout &lt;&lt; "VECTOR" &lt;&lt; endl; for( int i = 0; i &lt; 10000; i++ ) { lista.push_back( rand() % 100 ); cout &lt;&lt; lista[i] &lt;&lt; " | "; } cout &lt;&lt; endl; cout &lt;&lt; "******" &lt;&lt; endl; cout &lt;&lt; "QUICKSORT" &lt;&lt; endl; lista = quick( lista ); vector &lt; int &gt; :: const_iterator it; for( it = lista.begin(); it != lista.end(); ++it ) cout &lt;&lt; *it &lt;&lt; " | "; cout &lt;&lt; endl; } </code></pre>

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<p>I have the following code:</p> <pre><code>print o # {'actor_name': [u'Keanu Reeves', u'Laurence Fishburne', u'Carrie-Anne Moss', u'Hugo Weaving', u'Glor # ia Foster', u'Joe Pantoliano', u'Marcus Chong', u'Julian Arahanga', u'Belinda McClory', u'Matt Doran # '], 'played': [u'Neo (Thomas Anderson)', u'Morfeusz', u'Trinity', u'Agent Smith', u'Wyrocznia', u'Cy # pher', u'Tank', u'Apoc', u'Switch', u'Mouse']} li = list(o.itervalues()) for index, value in enumerate(li[0]): print [value, li[1][index]] # [u'Keanu Reeves', u'Neo (Thomas Anderson)'] # [u'Laurence Fishburne', u'Morfeusz'] # [u'Carrie-Anne Moss', u'Trinity'] # [u'Hugo Weaving', u'Agent Smith'] # [u'Gloria Foster', u'Wyrocznia'] # [u'Joe Pantoliano', u'Cypher'] # [u'Marcus Chong', u'Tank'] # [u'Julian Arahanga', u'Apoc'] # [u'Belinda McClory', u'Switch'] # [u'Matt Doran', u'Mouse'] </code></pre> <p>I'm curious how I could write this thing in a more Pythonic way without losing its readability.</p>

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<p>Is this the proper method for creating an OpenGL 3.3+ forward-compatible context?</p> <pre><code>// Create window WNDCLASSEX wc; ZeroMemory( &amp;wc, sizeof( wc ) ); wc.cbSize = sizeof( wc ); wc.lpfnWndProc = _eventHandler; wc.hInstance = GetModuleHandle( NULL ); wc.hIcon = LoadIcon( NULL, IDI_APPLICATION ); wc.hIconSm = LoadIcon( NULL, IDI_APPLICATION ); wc.hCursor = LoadCursor( NULL, IDC_ARROW ); wc.lpszClassName = "OpenGL 3.3"; if ( !RegisterClassEx( &amp;wc ) ) Error( "Failed to register window class!" ); if ( !( _window = CreateWindowEx( WS_EX_CLIENTEDGE, "OpenGL 3.3", "OpenGL 3.3", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, NULL, NULL, GetModuleHandle( NULL ), NULL ) ) ) Error( "Failed to create the window!" ); if ( !( _hdc = GetDC( _window ) ) ) Error( "Failed to retrieve device context!" ); // Choose pixel format int pixelFormat; PIXELFORMATDESCRIPTOR pfd; ZeroMemory( &amp;pfd, sizeof( pfd ) ); pfd.nSize = sizeof( pfd ); pfd.nVersion = 1; pfd.dwFlags = PFD_DOUBLEBUFFER | PFD_SUPPORT_OPENGL | PFD_DRAW_TO_WINDOW; pfd.iPixelType = PFD_TYPE_RGBA; pfd.cColorBits = 32; pfd.cDepthBits = 32; pfd.iLayerType = PFD_MAIN_PLANE; if ( !( pixelFormat = ChoosePixelFormat( _hdc, &amp;pfd ) ) ) Error( "Failed to find suitable pixel format!" ); if ( !SetPixelFormat( _hdc, pixelFormat, &amp;pfd ) ) Error( "Failed to set pixel format!" ); // Create temporary context and make sure we have support HGLRC tempContext = wglCreateContext( _hdc ); if ( !tempContext ) Error( "Failed to create temporary context!" ); if ( !wglMakeCurrent( _hdc, tempContext ) ) Error( "Failed to activate temporary context!" ); int major, minor; glGetIntegerv( GL_MAJOR_VERSION, &amp;major ); glGetIntegerv( GL_MINOR_VERSION, &amp;minor ); if ( major &lt; 3 || minor &lt; 2 ) Error( "OpenGL 3.2 is not supported!" ); // Create forward compatible context int attribs[] = { WGL_CONTEXT_MAJOR_VERSION_ARB, major, WGL_CONTEXT_MINOR_VERSION_ARB, minor, WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB, WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_CORE_PROFILE_BIT_ARB, 0 }; PFNWGLCREATEBUFFERREGIONARBPROC wglCreateContextAttribsARB = (PFNWGLCREATEBUFFERREGIONARBPROC)wglGetProcAddress( "wglCreateContextAttribsARB" ); if ( !wglCreateContextAttribsARB ) Error( "Failed to find pointer to wglCreateContextAttribsARB function!" ); if ( !( _context = wglCreateContextAttribsARB( _hdc, 0, (UINT)attribs ) ) ) Error( "Failed to create forward compatible context!" ); // Remove temporary context and activate forward compatible context wglMakeCurrent( NULL, NULL ); wglDeleteContext( tempContext ); if ( !wglMakeCurrent( _hdc, (HGLRC)_context ) ) Error( "Failed to activate forward compatible context!" ); // Show window ShowWindow( _window, SW_SHOW ); UpdateWindow( _window ); </code></pre> <p>It seems to work (gives GL_INVALID_OPERATION when using glBegin), but I just want to make sure this is the right way to go about it.</p>

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<p>The title sucks, but it's really very simple - given an array and a starting element, cycle between one element above, below, then two element above, and below the starting element. For example: </p> <pre><code>Start: 5 5 &gt; 6 &gt; 4 &gt; 7 &gt; 3 &gt; 8 &gt; 2 ... </code></pre> <p>It doesn't matter if the code initially start with the element above or below. To complicate things a little, when you reach the end or beginning of the array, the code should continue to pick valid array elements, instead of going into invalid positions:</p> <pre><code>Start: 2 2 &gt; 3 &gt; 1 &gt; 4 &gt; 0 &gt; 5 &gt; 6 &gt; 7 ... </code></pre> <p>This is the code I have. It works, but I don't really like the way to fulfil the second condition above, having that two lines repeated twice.</p> <pre><code>var distance = 0; while ((currentHeight + this.heights[index]) &lt; height) { sections.push(index); currentHeight += this.heights[index]; distance = -distance + (distance &gt;= 0 ? -1 : 1); index += distance; if (index &lt; 0 || index &gt;= this.heights.length) { distance = -distance + (distance &gt;= 0 ? -1 : 1); index += distance; } } </code></pre> <p><code>distance</code> is the distance from the starting point, <code>index</code> holds the current position. The code cycles with these two lines: </p> <pre><code>distance = -distance + (distance &gt;= 0 ? -1 : 1); index += distance; </code></pre> <p>and it resolves the invalid array position problem by simply rerunning those two lines if it finds an invalid array position. </p>

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<pre><code>$($(this).parent().parent().parent().parent().parent().parent().children()[0]).html() </code></pre>

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<p>A while back I wrote a <a href="http://brandontilley.com/2011/01/31/gist-tag-for-jekyll.html" rel="nofollow">Fluid tag for Jekyll</a> that inserts the contents of a <a href="https://gist.github.com/" rel="nofollow">GitHub Gist</a> into the content of the page in <code>&lt;noscript&gt;</code> tags for RSS readers. I've noticed a couple things I'm not happy with since posting it, but I am interested in the critique it will generate here on Stack Exchange!</p> <p>(Obviously, some of the internals regarding methods required to make Liquid tags work (such as the parameters to <code>initialize</code> and having a <code>render</code> method) aren't negotiable, but you get the idea.)</p> <pre><code>require 'digest/md5' require 'net/https' require 'uri' module Jekyll class GistTag &lt; Liquid::Tag def initialize(tag_name, text, token) super @text = text @cache = true @cache_folder = File.expand_path "../_gist_cache", File.dirname(__FILE__) end def render(context) return "" unless @text =~ /([\d]*) (.*)/ gist, file = $1.strip, $2.strip script_url = "https://gist.github.com/#{gist}.js?file=#{file}" code = get_cached_gist(gist, file) || get_gist_from_web(gist, file) code = code.gsub "&lt;", "&amp;lt;" string = "&lt;script src='#{script_url}'&gt;&lt;/script&gt;" string += "&lt;noscript&gt;&lt;pre&gt;&lt;code&gt;#{code}&lt;/code&gt;&lt;/pre&gt;&lt;/noscript&gt;" return string end def get_gist_url_for(gist, file) "https://gist.github.com/raw/#{gist}/#{file}" end def cache_gist(gist, file, data) file = get_cache_file_for gist, file File.open(file, "w+") do |f| f.write(data) end end def get_cached_gist(gist, file) return nil if @cache == false file = get_cache_file_for gist, file return nil unless File.exist?(file) return File.new(file).read end def get_cache_file_for(gist, file) bad_chars = /[^a-zA-Z0-9\-_\.]/ gist = gist.gsub bad_chars, '' file = file.gsub bad_chars, '' md5 = Digest::MD5.hexdigest "#{gist}-#{file}" File.join @cache_folder, "#{gist}-#{file}-#{md5}.cache" end def get_gist_from_web(gist, file) gist_url = get_gist_url_for(gist, file) raw_uri = URI.parse(gist_url) https = Net::HTTP.new(raw_uri.host, raw_uri.port) https.use_ssl = true https.verify_mode = OpenSSL::SSL::VERIFY_NONE request = Net::HTTP::Get.new(raw_uri.request_uri) data = https.request(request) data = data.body cache_gist(gist, file, data) unless @cache == false data end end class GistTagNoCache &lt; GistTag def initialize(tag_name, text, token) super @cache = false end end end Liquid::Template.register_tag('gist', Jekyll::GistTag) Liquid::Template.register_tag('gistnocache', Jekyll::GistTagNoCache) </code></pre>

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<p>I generally feel that the pattern I use for development is kind of wrong. I start with simple functionality, then when I realize that some pieces can be reused I usually start to write "scope root level" functions in order to be more DRY. I usually place these functions at the bottom of my "scope". Would these functions (<code>changeColumn</code>, in this case) better be methods of main object? Would this script better be organized in a more object-oriented way? Are there major problems with my coding style?</p> <p>Unfortunately, I work directly with back-end programmers who don't give a damn about JS and so I am left with myself at this. I am trying to look at “rock stars”, but they mainly write tools, not simple interaction functionality, so for this kind of scripts I rarely get to see examples of really good code to learn from.</p> <pre><code>/** Depends on: * - jQuery (tested with 1.5.1) * http://jquery.com/ * - jQuery scrolTo (tested with 1.4.2) * http://flesler.blogspot.com/2009/05/jqueryscrollto-142-released.html **/ // Main obj omami = { init: function() { // scrollable area var content = $('#content').css('overflow-x', 'scroll'), // flag identifying scroll event didScroll, // flag identifying if scroll event // is caused by mouse / trackpad etc. // i.e. user action userScroll, // flag identifying if scroll event // is caused by script action scriptScroll, // content sections cols = content.find('.column'), // hash table to store initial columns x-axis positions positionsMap = {}, currentColHash, // Checks if first argument is bigger than second // and smaller than third isInRange = function(num, a, b) { return (num &gt; a &amp;&amp; num &lt; b); }; // store initial columns positions cols.each(function() { var col = $(this); positionsMap[col.attr('id')] = col.position().left; }); // don't bind complex logic directly on scroll – // http://ejohn.org/blog/learning-from-twitter/ content.bind('scroll', function(e) { didScroll = true; }) // for each user initiated scroll event // poll current section setInterval(function() { if ( didScroll &amp;&amp; !scriptScroll ) { didScroll = false; var curScroll = content.scrollLeft(), colID; // find what column is selected for ( colID in positionsMap ) { // safe sex if ( {}.hasOwnProperty.call(positionsMap, colID) ) { // we compare current left scroll of container element // with initial positions of columns if ( isInRange(curScroll, positionsMap[colID] - 150, positionsMap[colID] + 410) ) { // cut "col-" from column ID currentColHash = colID.substring(4); // if current col isn't already selected if (location.hash.indexOf(currentColHash) == '-1') { // indicate user action userScroll = true; // highlight current column in the address bar location.hash = currentColHash; } } } } } }, 250); // Controller $(window).bind('hashchange', function() { var hash = location.hash; if (hash != '' &amp;&amp; hash != '#') { // cut '#' off hash = hash.substring(1); // don't override user action if (!userScroll) { // indicate that scroll happens programmatically scriptScroll = true; // do the scrolling content.scrollTo( ( content.scrollLeft() + $('#col-' + hash).position().left ) - 20 , 500, { onAfter: function() { // done with JavaScript scrolling // start polling current section again scriptScroll = false; } }); } userScroll = false; } else { // support back-button up to empty-hash state content.scrollTo(0); } // on page load, scroll to the proper section }).trigger('hashchange'); // scroll to the next/previous column controls // just updating location.hash // controller will take care of taking appropriate action $('.column .scroll').bind('click', function(e) { e.preventDefault(); var arrow = $(this); // change the column changeColumn({ direction : arrow.hasClass('right') ? 'right' : 'left', currentColumn : arrow.closest('.column') }); });// .scroll bind('click) fn // handle left and right arrows $(window).bind('keyup', function(e) { // 37 – left arrow // 39 - right arrow if (e.keyCode == 37 || e.keyCode == 39) { e.preventDefault(); changeColumn({ direction: (e.keyCode == 39) ? 'right' : 'left' }); } });// window bind('keyup') fn // updates location.hash with slug of the column // user wants to view, either by scrolling to it, // either by navigating to it with arrows/header nav // // @param {Object} options object // @option {String} direction – determens change direction // @option {jQuery} currentColumn – currently selected column function changeColumn(opts) { // defaults var settings = { direction : 'right', currentColumn : (function(){ // calculate current column from hash if it's selected var colHash = location.hash.substring(1); // if it's not, we suppose we are at first column return (colHash.length != 0) ? $('#col-' + colHash) : cols.first(); })() }; // merge options and defaults $.extend(settings, opts); // what's the next column? var nextColumn = (settings.direction == 'right') // scroll right ? (settings.currentColumn.next().length != 0) // scroll to the next column ? settings.currentColumn.next() // scroll to the first column : settings.currentColumn.siblings().first() // scroll left : (settings.currentColumn.prev().length != 0) // scroll to the previous column ? settings.currentColumn.prev() // scroll to the last column : settings.currentColumn.siblings().last(); // update the hash location.hash = nextColumn.attr('id').substring(4); }// fn changeColumn } // fn omami.init };// obj omami </code></pre>

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<p>I just realized that I could turn:</p> <pre><code>import MySQLdb def main(): db = MySQLdb.connect( .. ) try: while True: do_thingy() finally: db.close() </code></pre> <p>into:</p> <pre><code>import MySQLdb, atexit def main(): db = MySQLdb.connect( .. ) atexit.register( db.close ) while True: do_thingy() </code></pre> <p>Which lets me keep the code for closing the database next to the opening, and saves me a line of code and an indentation level, which I like. Is there a reason why I shouldn't do this?</p>

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<p>I have written these two functions that have a similar process. The first is meant to "split" a string on a given character and the second is meant to "replace-all" instances of a character in a given string. The behavior between the two seems very similar - can you think of a good way to abstract that behavior into a third, reusable, function? (which could be executed by calling, for example, (where-found sought-letter searchee-string thing-to-do)).</p> <pre><code>(defun split (separator splittee) (let ((next-index (position separator splittee))) (if next-index (cons (subseq splittee 0 next-index) (split separator (subseq splittee (1+ next-index)))) (list splittee)))) (defun replace-all (replacand replacee replacor) (let ((next-index (position replacand replacee))) (if next-index (concatenate 'string (subseq replacee 0 next-index) replacor (replace-all replacand (subseq replacee (1+ next-index)) replacor)) replacee))) </code></pre> <p>What do you think? Is this better than the original code, or is it too complicated?</p> <pre><code>(defun where-found (sought-letter the-string to-do-onroute to-do-on-leaf) (let ((next-index (position sought-letter the-string))) (if next-index (apply to-do-onroute (list (subseq the-string 0 next-index) (subseq the-string (1+ next-index)))) (apply to-do-on-leaf (list the-string))))) (defun split (separator splittee) (where-found separator splittee (lambda (pre-string post-string) (cons pre-string (split separator post-string))) (lambda (leaf-string) (list leaf-string)))) (defun replace-all (to-be-replaced-string the-patient-string the-replacement-string) (where-found to-be-replaced-string the-patient-string (lambda (pre-string post-string) (format t "pre: ~a post: ~a the-replacement-string: ~a ~%" pre-string post-string the-replacement-string) (concatenate 'string pre-string the-replacement-string (replace-all to-be-replaced-string post-string the-replacement-string))) (lambda (leaf-string) leaf-string))) (format t "the cat is here: ~a ~%" (replace-all #\Space "the cat is here" "")) (format t "the cat is here: ~a ~%" (split #\Space "the cat is here")) </code></pre>

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<p>I'm learning Python and have found <a href="http://code.google.com/codejam/contest/dashboard?c=635101#s=p0" rel="nofollow noreferrer">this problem</a> from Google Code Jam:</p> <blockquote> <p>How many <code>mkdir</code> commands does it take to construct a given directory tree:</p> <h3>Input</h3> <p>The first line of the input gives the number of test cases, <strong>T</strong>. <strong>T</strong> test cases follow. Each case begins with a line containing two integers <strong>N</strong> and <strong>M</strong>, separated by a space.</p> <p>The next <strong>N</strong> lines each give the path of one directory that already exists on your computer. This list will include every directory already on your computer other than the root directory. (The root directory is on every computer, so there is no need to list it explicitly.)</p> <p>The next <strong>M</strong> lines each give the path of one directory that you want to create.</p> <p>Each of the paths in the input is formatted as in the problem statement above. Specifically, a path consists of one or more lower-case alpha-numeric strings (i.e., strings containing only the symbols 'a'-'z' and '0'-'9'), each preceded by a single forward slash. These alpha-numeric strings are never empty.</p> <h3>Output</h3> <p>For each test case, output one line containing &quot;Case #x: y&quot;, where x is the case number (starting from 1) and y is the number of <code>mkdir</code> you need.</p> </blockquote> <p>I've solved it by writing code shown below, and it works correctly, but how can I make it faster?</p> <pre><code>import sys def split_path(path_file,line_count_to_be_read): for i in range(line_count_to_be_read): # Get the Path line line = path_file.readline() # Skip the first slash line = line[1:] line = line.strip() splited = line.split('/') # make each subpaths from the source path for j in range(1,len(splited)+1): joined = &quot;/&quot;.join(splited[:j]) yield joined def main(): file_name = &quot;&quot; try: file_name = sys.argv[1] except IndexError: file_name = &quot;A-small-practice.in&quot; with open(file_name) as path_file: # skip the first line line = path_file.readline() total_testcases = int(line) # Number of Test Cases - Unused case_no = 0 while True: line = path_file.readline() if not line: break # Get Existing path and New path count existing_count,new_count = line.split() existing_count = int(existing_count) new_count = int(new_count) # Split Every Path and Make all Subpaths existing_paths = list(split_path(path_file,existing_count)) # Existing Subpaths new_paths = list(split_path(path_file,new_count)) # New Subpaths # Remove all paths that is in Existing list from the New list new_mkdir_set = set(new_paths) - set(existing_paths) case_no += 1 # length of new_set contains number of needed mkdir(s) print &quot;Case #{0}: {1}&quot;.format(case_no,len(new_mkdir_set)) if __name__ == '__main__': main() </code></pre>

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<p>I initially posted this on StackOverflow, and was redirected here. I have been playing around with Bouncy Castle (Java) for the last few days, and I've reached the point where I believe I can securely exchange secret keys with a Diffie-Hellman exchange.</p> <p>Having read many posts underlining the difficulty of properly implementing a cryptographic exchange, I would like your honest opinion on my work. All the underlying cipher operations are based on Bouncy Castle and may therefore be deemed reliable.</p> <pre><code>String message = "Hello World"; AESCipher aes_client = new AESCipher(256); RSACipher rsa_server = new RSACipher(2048); // (Public key sent over the wire) RSACipher rsa_client = new RSACipher(rsa_server.getPublicKey().getModulus(), rsa_server.getPublicKey().getExponent()); // The client encodes his AES key with the RSA public key: byte[] aes_key = rsa_client.encode(aes_client.getKeyBytes()); byte[] aes_iv = rsa_client.encode(aes_client.getInitializationVector()); // (Data sent back over the wire) byte[] decoded_aes_key = rsa_server.decode(aes_key); byte[] decoded_aes_iv = rsa_server.decode(aes_iv); // The server creates an AES server which uses the client key: AESCipher aes_server = new AESCipher(decoded_aes_key, decoded_aes_iv); byte[] encoded_message = aes_client.encode(message.getBytes()); byte[] decoded_message = aes_server.decode(encoded_message); System.out.println(new String(decoded_message)); </code></pre> <p>Can this exchange be considered safe? Should I be sticking with SSL Sockets, eventhough it'd hurt to thrash my hard work? Thanks in advance for your input!</p> <p>(By the way, my Bouncy-Castle-Wrapping-Library is totally open-source, so just let me know if you want the repository's URL.)</p>

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<p>I have a heading, which is an integer and from it I would like to figure out the compass direction (North, North-East,...) and return the appropriate icon. I feel like I'm probably already at the cleanest solution but I would love to be proven wrong.</p> <pre><code>public GetHeadingImage(string iconName, int heading){ if (IsNorthHeading(heading)) return iconName + "n" + ICON_FILE_EXTENTION; if (IsNorthEastHeading(heading)) return iconName + "ne" + ICON_FILE_EXTENTION; if (IsEastHeading(heading)) return iconName + "e" + ICON_FILE_EXTENTION; /*A bunch more lines*/ } private bool IsNorthHeading(int heading) { return heading &lt; 23 || heading &gt; 337; } /* A bunch more extracted test methods*/ </code></pre>

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<p>I'll try to keep this as short as I can without losing context - we have a system for online education, where presentations often have a test.</p> <p>Management has access to a report used for measuring compliance. The report has a few paramaters that need to be selected:</p> <ul> <li>A date range to look in (e.g. From 11 March 2010 to 11 March 2011)</li> <li>One or more online tests (it's a hospital, so some topics have a clinical and a non-clinical version)</li> <li>One or more departments (so VPs can see all their departments, managers can see just their department, etc.)</li> <li>There are a couple of options for filtering the results (showing all results, showing only "missing" results - kinda broken at this point, excluding "missing" results)</li> <li>The report can be pulled as an Excel spreadsheet or as a web page (The Excel option is going to go away due to some issues with Excel 2007, I just haven't had time to remove it)</li> </ul> <p><strong>2011-03-17 Addendum:</strong></p> <p>As per <a href="https://codereview.stackexchange.com/questions/1298/trying-to-speed-up-a-report-that-takes-freaking-forever/1303#1303">munificent's advice</a> (and apparently an earlier me's notes) I used <a href="http://aspprofiler.sourceforge.net/" rel="nofollow noreferrer">http://aspprofiler.sourceforge.net/</a> to get a little more hard data.</p> <p>Getting the data from SQL Server Express 2005 (which is running on the same machine) seems to be the biggest culprit.</p> <p><code>Set objResultsRS = objSQLDB.Execute(,,adCmdText)</code> has taken anywhere from 33% to 50% of the processing time.</p> <p><code>If Not objResultsRS.BOF Then objResultsRS.MoveFirst</code> takes another 20% - 26% of the time - I'll be damned if I can figure out why its even running... since the data is getting dumped into an array, I probably don't need to check BOF and EOF to see if I've got an empty recordset - I just need to check if the array is empty. I'll test to see if that yields any improvements worth reporting.</p> <p>Nothing else is taking more than 3% of the processing time. I've run a fairly typical report checking system-wide compliance with two online test from 11 March 2010 to 11 March 2011. (a report that is being run constantly this month by just about every VP, and the source of half the support calls I've been taking.)</p> <p>The SQL for that run ends up looking like:</p> <pre><code>SELECT LEmp.LawsonID, LEmp.LastName, LEmp.FirstName, LEmp.MidInit, LEmp.winUserName, LPos.Position, LEmp.AccCode, LDept.DisplayName, LEmp.EmpStatus, Log.VerificationID, Log.WinLogon, Log.Name, Log.Position, Log.Pass, Log.DoneTime, Log.Title FROM ((Lawson_Employees AS LEmp LEFT JOIN Lawson_DeptInfo AS LDept ON LEmp.AccCode = LDept.AccCode) INNER JOIN Lawson_PositionCodes AS LPos ON LEmp.PosCode = LPos.PosCode) LEFT JOIN ( SELECT V.VerificationID, V.WinLogon, V.LawsonID, V.Name, V.Position, V.Pass, V.DoneTime, C.Title FROM Testing_TestLogs AS V LEFT JOIN Testing_Content AS C ON V.PresID = C.PresID WHERE V.PresID IN (284,285) AND V.DoneTime &gt;= '20100311000000' AND V.DoneTime &lt;= '20110311235959' AND V.Name &lt;&gt; 'program check' ) AS Log ON LEmp.LawsonID = Log.LawsonID WHERE LEmp.CurrentEmp = 1 AND LEmp.AccCode &lt;&gt; '106000' AND LEmp.EmpStatus NOT IN ('CT','EN','R1','R2','T1','T2','T3') ORDER BY LEmp.AccCode ASC, LEmp.LastName ASC, LEmp.FirstName ASC, Log.DoneTime ASC; </code></pre> <p><strong>2011-03-23 Addendum:</strong></p> <p>As much as I'd like to devote more time to this PITA, I've got other deadlines pressing in. The sub-query seems to be what is causing the most grief from the SQL Server end (<a href="https://codereview.stackexchange.com/questions/1298/trying-to-speed-up-a-report-that-takes-freaking-forever/1311#1311">thanks Mongus</a>), but I ran out of time to devote too much attention to it.</p> <p>By duming whatever was returned into the array anyway, and then checking if the array was empty, I was able to get a ~20% improvement. So that section now looks like this:</p> <pre><code>Dim objSQLDB : Set objSQLDB = CreateObject("ADODB.Command") objSQLDB.ActiveConnection = strTestingConn objSQLDB.CommandText = strSQL Set objResultsRS = objSQLDB.Execute(,,adCmdText) arrResults = objResultsRS.GetRows(adGetRowsRest) intTotResults = UBound(arrResults,2) objResultsRS.Close Set objResultsRS = Nothing Set objSQLDB = Nothing If Not IsArray(arrResults) Then 'No results, show the page then end the script' objResultsRS.Close Set objResultsRS = Nothing Set objSQLDB = Nothing Response.End() End If </code></pre> <hr> <p>I'm leaving the (somewhat snipped) code at the bottom for reference/context.</p> <pre><code>%&gt;&lt;!-- #include virtual="/educationtesting/inc_testingstuff.asp" --&gt;&lt;% '--&gt; Removed some variable declarations that are used by the library below, but not in the main code below &lt;--' %&gt;&lt;!-- #include virtual="/forum/inc_func_common.asp"--&gt;&lt;% '--&gt; Removed declarations and validation of incoming data &lt;--' strSQL = "SELECT LEmp.LawsonID, LEmp.LastName, LEmp.FirstName, LEmp.MidInit, LEmp.winUserName, LPos.Position, LEmp.AccCode, LDept.DisplayName, LEmp.EmpStatus, " strSQL = strSQL &amp; "Log.VerificationID, Log.WinLogon, Log.Name, Log.Position, Log.Pass, Log.DoneTime, Log.Title " strSQL = strSQL &amp; "FROM ((Lawson_Employees AS LEmp LEFT JOIN Lawson_DeptInfo AS LDept ON LEmp.AccCode = LDept.AccCode) " strSQL = strSQL &amp; "INNER JOIN Lawson_PositionCodes AS LPos ON LEmp.PosCode = LPos.PosCode) " strSQL = strSQL &amp; "LEFT JOIN " strSQL = strSQL &amp; "(SELECT V.VerificationID, V.WinLogon, V.LawsonID, V.Name, V.Position, V.Pass, V.DoneTime, C.Title " strSQL = strSQL &amp; "FROM Testing_TestLogs AS V LEFT JOIN Testing_Content AS C ON V.PresID = C.PresID " strSQL = strSQL &amp; "WHERE V.PresID IN (" &amp; intPresID &amp; ") " strSQL = strSQL &amp; "AND V.DoneTime &gt;= '" &amp; strFrom &amp; "' AND V.DoneTime &lt;= '" &amp; strTo &amp; "' " strSQL = strSQL &amp; "AND V.Name &lt;&gt; 'program check') " strSQL = strSQL &amp; "AS Log ON LEmp.LawsonID = Log.LawsonID " strSQL = strSQL &amp; "WHERE LEmp.CurrentEmp = 1 " Select Case LCase(strAccCode) Case "all" Case "mgmt" strSQL = strSQL &amp; "AND (LDept.VP = '" &amp; Session(strCookieURL &amp; "strWinFullName") &amp; "' " strSQL = strSQL &amp; "OR LDept.SLD = '" &amp; Session(strCookieURL &amp; "strWinFullName") &amp; "' " strSQL = strSQL &amp; "OR LDept.DeptMgr = '" &amp; Session(strCookieURL &amp; "strWinFullName") &amp; "') " Case Else strSQL = strSQL &amp; "AND LEmp.AccCode IN (" &amp; strAccCode &amp; ") " End Select 'Filter out the suspense account' strSQL = strSQL &amp; "AND LEmp.AccCode &lt;&gt; '106000' " 'Filter out LOA, FMLA, etc.' strSQL = strSQL &amp; "AND LEmp.EmpStatus NOT IN ('CT','EN','R1','R2','T1','T2','T3') " Dim strRptHead : strRptHead = "" Select Case UCase(Trim(Request.Form("Filter"))) Case "C" strSQL = strSQL &amp; "AND Log.VerificationID IS NOT NULL " strSQL = strSQL &amp; "ORDER BY LEmp.AccCode ASC, LEmp.LastName ASC, LEmp.FirstName ASC, Log.DoneTime ASC;" strRptHead = "Only completed records" Case "NC" strSQL = strSQL &amp; "AND Log.VerificationID IS NULL " strSQL = strSQL &amp; "ORDER BY LEmp.AccCode ASC, LEmp.LastName ASC, LEmp.FirstName ASC;" strRptHead = "All missing records" Case Else strSQL = strSQL &amp; "ORDER BY LEmp.AccCode ASC, LEmp.LastName ASC, LEmp.FirstName ASC, Log.DoneTime ASC;" strRptHead = "All compliance results" End Select Dim objResultsRS, arrResults, intTotResults Dim objSQLDB : Set objSQLDB = CreateObject("ADODB.Command") objSQLDB.ActiveConnection = strTestingConn objSQLDB.CommandText = strSQL Set objResultsRS = objSQLDB.Execute(,,adCmdText) If Not objResultsRS.BOF Then objResultsRS.MoveFirst If objResultsRS.EOF Then 'No results, show the page then end the script' '--&gt; Snipped code that showed message re: no records, and what may be at issue &lt;--' objResultsRS.Close Set objResultsRS = Nothing Set objSQLDB = Nothing Response.End() Else 'Results, drop the recordset into an array and close out the DB connection' arrResults = objResultsRS.GetRows(adGetRowsRest) intTotResults = UBound(arrResults,2) objResultsRS.Close Set objResultsRS = Nothing Set objSQLDB = Nothing End If 'send mime type et al for headings' Select Case strDisplay Case "page" '--&gt; Snipped code to write out HTML header info &lt;--' Case "excel" 'Returns the result as an Excel spread sheet.' Response.ContentType = "application/vnd.ms-excel" Response.AddHeader "content-disposition","attachment;filename=AllResults_" &amp; strFrom &amp; "_To_" &amp; strTo &amp; ".xls" '--&gt; Snipped code to write out Excel header info &lt;--' Case Else Response.Redirect("oops.asp?Err=BadDisplay") End Select Select Case strDisplay Case "page" Response.Write("&lt;table class=""fcc iffc c tc tbc"" cellspacing=""0"" style=""font-size:8pt;""&gt;" &amp; vbNewLine) If LCase(strAccCode) = "mgmt" Then '--&gt; Show a note to managers re: what to do if a department is/not on the list that should/not be there &lt;--' End If '--&gt; Write out the main report header, formatted for a web page &lt;--' strExcelExtra = "" Case "excel" '--&gt; Write out the main report header, formatted for an Excel sheet &lt;--' strExcelExtra = " style=""mso-number-format:\@;""" Case Else Response.Redirect("oops.asp?Err=BadDisplay") End Select '--&gt; Removed some declarations for variables used below &lt;--' 'Write out each row of data' '--&gt; Removed the horridly long chunk of code for writing out each row - profiler showed it was not that big of a time suck &lt;--' 'Done, close up table' Response.Write("&lt;/table&gt;" &amp; vbNewLine) If strDisplay = "page" Then Response.Write("&lt;h3 class=""c""&gt;&lt;a href=""#"" onClick=""window.close()""&gt;Close this window&lt;/a&gt;&lt;/h3&gt;" &amp; vbNewLine &amp; "&lt;/center&gt;" &amp; vbNewLine) Response.Write("&lt;/body&gt;" &amp; vbNewLine &amp; "&lt;/html&gt;") %&gt; </code></pre> <p><strong>Footnote:</strong> Don't think it will matter, but I will be stripping out the Excel support sometime in the near future. As a dev team of 1 (and server admin, db admin, designer, tester, maintainer, etc.), there are a couple other projects that need to get finished before I can do that.</p>

1298

<p>One of my side projects is a table driven scanner/parser generator, in an effort to reduce the size of the transition table I represent the generated table <code>A[x, y]</code> as <code>A'[x + I[y]]</code> instead of <code>A'[x + y * c]</code>. This allows me to overlap identical parts of the table.</p> <p>The following is the code responsible for actually arranging the rows. I'm not very happy with it, particularly the number of arrays that need to be constructed. Any improvements to readability/performance/effectiveness would be much appreciated.</p> <pre><code>/// &lt;remarks&gt; /// A two dimentional array, or table, can be represented by a single dimentional table /// where the data for position (x, y) is stored at index x + table_width * y. If the /// table is read-only then the multiplication can be replaced with an index lookup /// allowing identical portions of the table to be overlapped thus (depending on the /// data) reducing the memory footprint of the table. /// /// The purpose of this class is to take a bunch of rows and try to find an arrangement /// with a good approximation of the minimal space required. Finding the optimal solution /// reduces to the "Traveling Sailsman Problem", so a good approximation is sufficient. /// /// This particular algorithm is intended to work with the characteristics of the sparse /// state transition tables of the lexer/parser and will probably perform very poorly /// for other cases. /// /// Algorithm Overview: /// /// * If two fragments with the same content are encountered, they are combined with /// identical offsets. /// /// * Each fragment gets two tags, one for each end. all start tags are put into one list /// and all end tags in another. /// /// * Sort both lists first by "end value" (the very first value for a start tag and the /// very last value for an end tag) and second by "end length" (the number of /// consecutive times "end value" appears) in descending order. /// /// * Make a single pass over both lists at the same time, combining distinct fragments /// with the longest sequence of an identical value. /// /// * All remaining fragments are appended end to end. /// &lt;/remarks&gt; [DebuggerDisplay("Count = {Count}")] internal sealed class TableFragment : IList&lt;int&gt;, ICollection { public TableFragment(int[] values, int state) : this(values, new int[] { state }, new int[] { 0 }, 0) { } public TableFragment(int[] values, int state, int skip) : this(values, new int[] { state }, new int[] { -skip }, skip) { } TableFragment(int[] values, int[] states, int[] offsets, int skip) { this._skip = skip; this._values = values; this._states = states; this._offsets = offsets; } /// &lt;summary&gt; /// Attempt to combine multiple TableFragments into a single fragment. /// &lt;/summary&gt; /// &lt;remarks&gt; /// This method attempts to minimise the total length of the result by adjusting the /// offsets so that identical portions overlap. /// &lt;/remarks&gt; public static TableFragment Combine(IList&lt;TableFragment&gt; fragments) { if (fragments == null) throw new ArgumentNullException("fragments"); if (fragments.Count == 0) throw new ArgumentException("fragments list cannot be empty", "fragments"); List&lt;TableFragmentTag&gt; startTags = new List&lt;TableFragmentTag&gt;(fragments.Count); List&lt;TableFragmentTag&gt; endTags = new List&lt;TableFragmentTag&gt;(fragments.Count); Dictionary&lt;int, List&lt;TableFragmentTag&gt;&gt; map = new Dictionary&lt;int, List&lt;TableFragmentTag&gt;&gt;(); for (int i = 0; i &lt; fragments.Count; i++) { TableFragmentTag startTag; TableFragmentTag endTag; int hash; CreateTags(fragments[i], out startTag, out endTag, out hash); List&lt;TableFragmentTag&gt; list; if (!map.TryGetValue(hash, out list)) { list = new List&lt;TableFragmentTag&gt;(); list.Add(startTag); map.Add(hash, list); startTags.Add(startTag); endTags.Add(endTag); } else if (!AddEquivilenceList(list, startTag)) { startTags.Add(startTag); endTags.Add(endTag); } } startTags.Sort(Comparison); endTags.Sort(Comparison); LinkedList&lt;TableFragmentTag&gt; startFragments = new LinkedList&lt;TableFragmentTag&gt;(startTags); LinkedList&lt;TableFragmentTag&gt; endFragments = new LinkedList&lt;TableFragmentTag&gt;(endTags); return Combine(startFragments, endFragments); } /// &lt;summary&gt; /// Indicates the number of "don't care" elements between the offset origin and the first value. /// &lt;/summary&gt; /// &lt;remarks&gt; /// This is useful if it is known that the first N elements can never be used, and as such can have /// any value. /// &lt;/remarks&gt; public int Skip { [DebuggerStepThrough] get { return _skip; } } public int this[int index] { [DebuggerStepThrough] get { return _values[index]; } } /// &lt;summary&gt; /// Gets the offset into this fragment where the values associated with the given state can be found. /// &lt;/summary&gt; /// &lt;remarks&gt; /// Returns null if the state was never combined into this fragment. /// &lt;/remarks&gt; public int? GetOffset(int state) { int index = Array.BinarySearch(_states, state); return index &lt; 0 ? new int?() : _offsets[index]; } static void CreateTags(TableFragment fragment, out TableFragmentTag startTag, out TableFragmentTag endTag, out int hash) { if (fragment == null) throw new ArgumentNullException("fragment"); int[] values = fragment._values; int startIndex = 0; int startValue = values[0]; int endIndex = 0; int endValue = values[values.Length - 1]; uint currentHash = 0; bool startSet = false; for (int i = 0; i &lt; values.Length; i++) { int val = values[i]; if (!startSet &amp;&amp; val != startValue) { startSet = true; startIndex = i; } if (val != endValue) { endIndex = i; } currentHash = unchecked(((currentHash &gt;&gt; 5) | (currentHash &lt;&lt; 27)) ^ (uint)val); } startTag = new TableFragmentTag() { Fragment = fragment, EndLen = startSet ? startIndex : values.Length, EndValue = startValue, }; endTag = new TableFragmentTag() { Fragment = fragment, EndLen = startSet ? values.Length - endIndex - 1 : values.Length, EndValue = endValue, }; startTag.Partner = endTag; endTag.Partner = startTag; hash = (int)currentHash; } /// &lt;summary&gt; /// Replace the TableFragments referenced by the two tags with a single fragment that /// contains their combined values. /// &lt;/summary&gt; /// &lt;remarks&gt; /// The end of tag1 will be made to overlap the start of tag2 as far as possible. /// &lt;/remarks&gt; static void Combine(TableFragmentTag tag1, TableFragmentTag tag2) { int overlap; if (tag1.EndValue != tag2.EndValue) { overlap = 0; } else { overlap = Math.Min(tag1.EndLen, tag2.EndLen); } TableFragment fragment = Combine(tag1.Fragment, tag2.Fragment, overlap); tag1.Partner.Fragment = fragment; tag2.Partner.Fragment = fragment; tag1.Partner.Partner = tag2.Partner; tag2.Partner.Partner = tag1.Partner; } static TableFragment Combine(TableFragment fragment1, TableFragment fragment2, int overlap) { int[] values1 = fragment1._values; int[] values2 = fragment2._values; int[] states1 = fragment1._states; int[] states2 = fragment2._states; int[] offsets1 = fragment1._offsets; int[] offsets2 = fragment2._offsets; int offset = values1.Length - overlap; int[] values = new int[offset + values2.Length]; int[] states = new int[states1.Length + states2.Length]; int[] offsets = new int[states.Length]; Array.Copy(values1, values, offset); Array.Copy(values2, 0, values, offset, values2.Length); int read1 = 0; int read2 = 0; int write = 0; while (read1 &lt; states1.Length &amp;&amp; read2 &lt; states2.Length) { int diff = states1[read1] - states2[read2]; if (diff == 0) throw new InvalidOperationException("attempting to combine 2 fragments that both contain the state " + states1[read1]); if (diff &lt; 0) { states[write] = states1[read1]; offsets[write] = offsets1[read1]; write++; read1++; } else { states[write] = states2[read2]; offsets[write] = offsets2[read2] + offset; write++; read2++; } } while (read1 &lt; states1.Length) { states[write] = states1[read1]; offsets[write] = offsets1[read1]; write++; read1++; } while (read2 &lt; states2.Length) { states[write] = states2[read2]; offsets[write] = offsets2[read2] + offset; write++; read2++; } return new TableFragment(values, states, offsets, Math.Max(fragment1.Skip, fragment2.Skip - offset)); } static TableFragment Combine(LinkedList&lt;TableFragmentTag&gt; startFragmentTags, LinkedList&lt;TableFragmentTag&gt; endFragmentTags) { LinkedList&lt;TableFragmentTag&gt; finalFragments = new LinkedList&lt;TableFragmentTag&gt;(); while (startFragmentTags.Count &gt; 0 &amp;&amp; endFragmentTags.Count &gt; 0) { LinkedListNode&lt;TableFragmentTag&gt; tailNode = startFragmentTags.First; LinkedListNode&lt;TableFragmentTag&gt; leadNode = endFragmentTags.First; if (tailNode.Value.Fragment == leadNode.Value.Fragment) { // if the tailNode and leadNode reference the same fragment, then try to replace one // of them as bad things happen when overlapping a fragment with itself. if (leadNode.Next != null) { leadNode = leadNode.Next; } else if (tailNode.Next != null) { tailNode = tailNode.Next; } else { startFragmentTags.Remove(tailNode); finalFragments.AddLast(tailNode); break; } } int leadEnd = leadNode.Value.EndValue; int tailStart = tailNode.Value.EndValue; if (leadEnd &lt; tailStart) { endFragmentTags.Remove(leadNode); } else if (tailStart &lt; leadEnd) { startFragmentTags.Remove(tailNode); finalFragments.AddLast(tailNode); } else { endFragmentTags.Remove(leadNode); startFragmentTags.Remove(tailNode); TableFragment.Combine(leadNode.Value, tailNode.Value); } } while (startFragmentTags.Count &gt; 0) { LinkedListNode&lt;TableFragmentTag&gt; node = startFragmentTags.First; startFragmentTags.Remove(node); finalFragments.AddLast(node); } return ForceCombine(finalFragments); } /// &lt;summary&gt; /// Append all fragments end to end without any attempt to overlap any of them. /// &lt;/summary&gt; /// &lt;remarks&gt; /// Used as a last resort for when all attempts to overlap the fragments have failed. /// &lt;/remarks&gt; static TableFragment ForceCombine(LinkedList&lt;TableFragmentTag&gt; finalFragments) { int totalLen = 0; int totalStates = 0; foreach (TableFragmentTag tag in finalFragments) { TableFragment fragment = tag.Fragment; totalLen += fragment._values.Length; totalStates += fragment._states.Length; } int newSkip = 0; int[] newValues = new int[totalLen]; int[] newStates = new int[totalStates]; int[] newOffsets = new int[totalStates]; totalLen = 0; totalStates = 0; foreach (TableFragmentTag tag in finalFragments) { TableFragment fragment = tag.Fragment; int[] values = fragment._values; int[] states = fragment._states; int[] offsets = fragment._offsets; newSkip = Math.Max(newSkip, tag.Fragment.Skip - totalLen); Array.Copy(states, 0, newStates, totalStates, states.Length); Array.Copy(values, 0, newValues, totalLen, values.Length); for (int i = 0; i &lt; states.Length; i++) { newOffsets[i + totalStates] = offsets[i] + totalLen; } totalLen += values.Length; totalStates += states.Length; } Array.Sort(newStates, newOffsets); return new TableFragment(newValues, newStates, newOffsets, newSkip); } /// &lt;remarks&gt; /// check for fragments with the same values, if one is found then combine them, otherwise add startTag to the list. /// &lt;/remarks&gt; static bool AddEquivilenceList(List&lt;TableFragmentTag&gt; list, TableFragmentTag startTag) { for (int i = 0; i &lt; list.Count; i++) { TableFragmentTag existingTag = list[i]; TableFragment existing = existingTag.Fragment; TableFragment fragment = startTag.Fragment; if (ValuesEquivilent(existing._values, fragment._values)) { existingTag.Partner.Fragment = existingTag.Fragment = Combine(existing, fragment, existing.Count); return true; } } list.Add(startTag); return false; } static bool ValuesEquivilent(int[] values1, int[] values2) { if (values1.Length != values2.Length) return false; for (int i = 0; i &lt; values1.Length; i++) { if (values1[i] != values2[i]) return false; } return true; } static int Comparison(TableFragmentTag tag1, TableFragmentTag tag2) { int diff = tag1.EndValue - tag2.EndValue; return diff != 0 ? diff : tag2.EndLen - tag1.EndLen; } #region IList&lt;int&gt; Members // ... #endregion #region ICollection&lt;int&gt; Members public void CopyTo(int[] array, int arrayIndex) { Array.Copy(_values, 0, array, arrayIndex, _values.Length); } // ... #endregion #region ICollection Members // ... #endregion #region IEnumerable&lt;int&gt; Members // ... #endregion #region IEnumerable Members // ... #endregion /// &lt;summary&gt; /// The TableFragmentTag class is a reference to one end of a TableFragment, either the start or the end. /// &lt;/summary&gt; [DebuggerDisplay("{EndValue} x {EndLen}")] sealed class TableFragmentTag { /// &lt;summary&gt; /// The Fragment this tag references. /// &lt;/summary&gt; public TableFragment Fragment { get; set; } /// &lt;summary&gt; /// The tag for the other end of the fragment. /// &lt;/summary&gt; public TableFragmentTag Partner { get; set; } /// &lt;summary&gt; /// The value at this end of the fragment. /// &lt;/summary&gt; public int EndValue { get; set; } /// &lt;summary&gt; /// The number of consecitive times EndValue appears. /// &lt;/summary&gt; public int EndLen { get; set; } } [DebuggerBrowsable(DebuggerBrowsableState.Never)] readonly int _skip; readonly int[] _values; readonly int[] _states; readonly int[] _offsets; } </code></pre> <hr> <p>And here is a simple example of how can be used.</p> <pre><code>int[][] table = GenerateTable(); TableFragment[] fragments = new TableFragment[table.Length]; for (int state = 0; state &lt; table.Length; state++) { fragments[state] = new TableFragment(table[state], state); } TableFragment result = TableFragment.Combine(fragments); int[] A = new int[result.Count + result.Skip]; result.CopyTo(A, result.Skip); int[] I = new int[table.Length]; for (int state = 0; state &lt; table.Length; state++) { I[state] = result.GetOffset(state).Value; } </code></pre>

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<p>As you review this, please keep in mind I'm using Jython 2.1 as shipped with IBM's WebSphere 7.0 (their latest-and-greatest). I don't have decorators, properties, new style objects, or any other Python feature invented in the last decade.</p> <p>Problem:</p> <p>Using WebSphere's Jython interface to determine app server configuration information is not exactly fast. I had already begun work on a simple Jython module to encapsulate the convoluted WebSphere Jython API when I decided to try and cache the results of each method invocation. WebSphere configuration details tend not to change very often. </p> <p>Inspired by Python 3.2's @functools.lru_cache and Python 2.2's properties I came up with:</p> <pre><code>from org.python.core import PyString, PyTuple class Getter: def getter(self,attr,valid_attrs): if attr == 'valid_attrs': return valid_attrs if attr not in valid_attrs.keys(): raise AttributeError attr_value = None if type(valid_attrs[attr]) == PyString: function = getattr(self,valid_attrs[attr]) attr_value = function() elif type(valid_attrs[attr]) == PyTuple: function = getattr(self,valid_attrs[attr][0]) args = [] kwargs = {} for arg in valid_attrs[attr][1:]: if type(arg) == PyTuple: if len(arg) &gt; 2: err = ('Named argument tuple %s in %s length &gt; 2.' % (arg, self.__class__.__name__ )) raise NameError(err) kwargs[arg[0]] = arg[1] elif type(arg) == PyString: args.append(arg) else: err = ('Unknown argument in %s __getattr__ dispatch list' % self.__class__.__name__ ) raise NameError(err) attr_value = function(*args,**kwargs) else: raise AttributeError return attr_value class App(Getter): def __init__(self, name=None): if name: self.app_name = name else: print 'App instance requires name.' raise NameError def __getattr__(self,attr): valid_attrs = { 'app_id': ('get_app_id'), 'deployed_nodes': ('get_deployed_nodes'), 'deployed_servers': ('get_deployed_servers'), } attr_value = Getter.getter(self,attr,valid_attrs) setattr(self,attr,attr_value) return attr_value def get_app_id(self): return AdminConfig.getid('/Deployment: %s/' % self.app_name) def get_deployed_node(self): ### ... def get_deployed_servers(self): ### ... </code></pre> <p>As I use this in other classes I change the function dispatch dict (<code>valid_attrs</code>) as needed.</p> <p>Is this an evil abuse of <code>__getattr__</code>? Next to code execution speed, I'm most worried about maintainability. Does this trigger a "WTF?" Or, does it make sense when viewed against the limitations of Jython 2.1 and features, such as @property, found in newer versions?</p>

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<p>I have a word-wrap algorithm that basically generates lines of text that fit the width of the text. Unfortunately, it gets slow when I add too much text.</p> <p>I was wondering if I oversaw any major optimizations that could be made. Also, if anyone has a design that would still allow strings of lines or string pointers of lines that is better I'd be open to rewriting the algorithm.</p> <p>Thanks</p> <pre><code>void AguiTextBox::makeLinesFromWordWrap() { textRows.clear(); textRows.push_back(""); std::string curStr; std::string curWord; int curWordWidth = 0; int curLetterWidth = 0; int curLineWidth = 0; bool isVscroll = isVScrollNeeded(); int voffset = 0; if(isVscroll) { voffset = pChildVScroll-&gt;getWidth(); } int AdjWidthMinusVoffset = getAdjustedWidth() - voffset; int len = getTextLength(); int bytesSkipped = 0; int letterLength = 0; size_t ind = 0; for(int i = 0; i &lt; len; ++i) { //get the unicode character letterLength = _unicodeFunctions.bringToNextUnichar(ind,getText()); curStr = getText().substr(bytesSkipped,letterLength); bytesSkipped += letterLength; curLetterWidth = getFont().getTextWidth(curStr); //push a new line if(curStr[0] == '\n') { textRows.back() += curWord; curWord = ""; curLetterWidth = 0; curWordWidth = 0; curLineWidth = 0; textRows.push_back(""); continue; } //ensure word is not longer than the width if(curWordWidth + curLetterWidth &gt;= AdjWidthMinusVoffset &amp;&amp; curWord.length() &gt;= 1) { textRows.back() += curWord; textRows.push_back(""); curWord = ""; curWordWidth = 0; curLineWidth = 0; } //add letter to word curWord += curStr; curWordWidth += curLetterWidth; //if we need a Vscroll bar start over if(!isVscroll &amp;&amp; isVScrollNeeded()) { isVscroll = true; voffset = pChildVScroll-&gt;getWidth(); AdjWidthMinusVoffset = getAdjustedWidth() - voffset; i = -1; curWord = ""; curStr = ""; textRows.clear(); textRows.push_back(""); ind = 0; curWordWidth = 0; curLetterWidth = 0; curLineWidth = 0; bytesSkipped = 0; continue; } if(curLineWidth + curWordWidth &gt;= AdjWidthMinusVoffset &amp;&amp; textRows.back().length() &gt;= 1) { textRows.push_back(""); curLineWidth = 0; } if(curStr[0] == ' ' || curStr[0] == '-') { textRows.back() += curWord; curLineWidth += curWordWidth; curWord = ""; curWordWidth = 0; } } if(curWord != "") { textRows.back() += curWord; } updateWidestLine(); } </code></pre>

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<blockquote> <p><strong>3.1</strong></p> <p>Write a program that computes the arithmetic sum of a constant difference sequence:</p> <pre><code>D0 = A Dn+1 = Cdn + B </code></pre> <p>Run the following values and compare to the closed form solution:</p> <pre><code>Maximum index = 10,000, a = 1:0; c = 5; b = 2^-15 </code></pre> </blockquote> <p>I am not sure I perfectly understand the problem above or how to confirm that I have the correct answer, but I wrote the following short program and I would appreciate any feedback.</p> <pre><code>(defun d-n-plus-1 (d-n c b) (+ (* d-n c) b)) (defun d-depth (depth d-n c b a) (if (equal depth 0) (d-n-plus-1 d-n c b) (d-depth (1- depth) (if (null d-n) a (d-n-plus-1 d-n c b)) c b a))) (format t "result: ~a ~%" (d-depth 10000 nil 5 (expt 2 -15) 1)) </code></pre> <p>In addition, I wrote a version that just uses a loop. I'm not crazy about "loop for x from 1 to depth" or that I used setq in this version. Can you think of a better way? Any other suggestions for this version are also welcome.</p> <pre><code>(defun d_n+1 (d_n c b) (+ (* d_n c) b)) (defun d-depth (depth d_n c b) (loop for x from 0 to depth do (setq d_n (d_n+1 d_n c b))) d_n) (format t "result: ~a ~%" (d-depth 10000 1 5 (expt 2 -15))) </code></pre>

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<p>I was asked to update a business rule to allow a specific column to be added. Because our datalayer uses only DataSets as an interface to the database that is what we work with in the business layer.</p> <p>Here I have created a couple of <code>DataTable</code> and <code>DataRow</code> extensions to use for this businessrule and I would like your opinion on things I might have missed. This is the method I use to search for changes:</p> <pre><code>private static bool hasColumnChanged(StringComparison stringComparison, bool ignoreWhitespace, DataRow row, DataColumn col) { bool isEqual = true; if (row[col, DataRowVersion.Original] != DBNull.Value &amp;&amp; row[col, DataRowVersion.Current] != DBNull.Value) { if (ignoreWhitespace) isEqual = row[col, DataRowVersion.Original].ToString().Trim().Equals(row[col, DataRowVersion.Current].ToString().Trim(), stringComparison); else isEqual = row[col, DataRowVersion.Original].ToString().Equals(row[col, DataRowVersion.Current].ToString(), stringComparison); } else isEqual = row[col, DataRowVersion.Original].Equals(row[col, DataRowVersion.Current]); return !isEqual; } </code></pre> <p>And these are simply the extensions using the code:</p> <pre><code>public static List&lt;DataColumn&gt; GetChangedColumns(this DataTable table) { return table.GetChangedColumns(StringComparison.InvariantCultureIgnoreCase, false); } public static List&lt;DataColumn&gt; GetChangedColumns(this DataTable table, bool ignoreWhitespace) { return table.GetChangedColumns(StringComparison.InvariantCultureIgnoreCase, ignoreWhitespace); } public static List&lt;DataColumn&gt; GetChangedColumns(this DataTable table, StringComparison stringComparison, bool ignoreWhitespace) { if (table == null) throw new ArgumentNullException("table"); List&lt;DataColumn&gt; columnsChanged = new List&lt;DataColumn&gt;(); foreach (DataRow row in table.GetChanges().Rows) { foreach (DataColumn col in row.Table.Columns) { if (!columnsChanged.Contains(col) &amp;&amp; hasColumnChanged(stringComparison, ignoreWhitespace, row, col)) columnsChanged.Add(col); } } return columnsChanged; } public static List&lt;DataColumn&gt; GetChangedColumns(this DataRow row) { return row.GetChangedColumns(StringComparison.InvariantCultureIgnoreCase, false); } public static List&lt;DataColumn&gt; GetChangedColumns(this DataRow row, bool ignoreWhitespace) { return row.GetChangedColumns(StringComparison.InvariantCultureIgnoreCase, ignoreWhitespace); } public static List&lt;DataColumn&gt; GetChangedColumns(this DataRow row, StringComparison stringComparison, bool ignoreWhitespace) { if (row == null) throw new ArgumentNullException("row"); List&lt;DataColumn&gt; columnsChanged = new List&lt;DataColumn&gt;(); foreach (DataColumn col in row.Table.Columns) { if (!columnsChanged.Contains(col) &amp;&amp; hasColumnChanged(stringComparison, ignoreWhitespace, row, col)) columnsChanged.Add(col); } return columnsChanged; } </code></pre> <p>To test the above code I use this simple unit test:</p> <pre><code>[TestMethod] public void DataTableAndDataRowGetChangedColumns() { DataSet ds = GetDummyDataSet(); ds.Tables[0].Rows[0][3] = DateTime.Now; ds.Tables[0].Rows[0][2] = ds.Tables[0].Rows[1][2].ToString() + " "; ds.Tables[0].Rows[0][1] = DBNull.Value; List&lt;DataColumn&gt; changesForRow = ds.Tables[0].Rows[0].GetChangedColumns(true); List&lt;DataColumn&gt; changesForTable = ds.Tables[0].GetChangedColumns(true); // For now we just verify if the amount of changes is the same (ez way out) Assert.IsTrue(changesForRow.Count.Equals(changesForTable.Count)); } </code></pre> <p>In the business rule I have implemented this piece of code which verifies if there are other datacolumns that have changed:</p> <pre><code>List&lt;DataColumn&gt; columnsChanged = dsChanges.Tables[0].GetChangedColumns(true); if(columnsChanged.Any(c=&gt;!c.ColumnName.Equals("DateUntill", StringComparison.InvariantCultureIgnoreCase))) throw new BusinessException("This premium can not be changed, only DateUntill can still change"); </code></pre>

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<p>I have the following 'custom' tree data structure. This concept was to be thought of as, if given ("abb", 20) and ("abc", 30), then</p> <blockquote> <pre><code>Tree['a']['b']['b'] == 20 </code></pre> </blockquote> <p></p> <blockquote> <pre><code>Tree['a']['b']['c'] == 30 </code></pre> </blockquote> <p>Or</p> <blockquote> <pre><code>a \ b / \ b c </code></pre> </blockquote> <p>With b == 30, and c == 20.</p> <p>Therefore taking up very limited space, and a very fast search. However, as depth increases, the number of bytes for a fully explored tree was exponential. In the above case, 4 * 256 bytes were required for valid indexing to occur. This was not good.</p> <p>It now works in the following way; for each branch, compare its value against the n character; i.e. introducing a worst case O(256) character comparison for each depth. This is not ideal, and what I want to attempt to change.</p> <hr> <p>The other question was (and still is), what is it? I couldn't quite classify it as anything but a Tree; nor relate it to any <code>std::</code> containers for comparison. It is very good at what it does though, out-performing a <code>std::map</code> with small strings and very large strings (sizes ~20, ~500 respectively); past 600, the data structure begins to get too heavy.</p> <p>Obviously, this code is a bit sketchy in how it handles the templates at the moment. A number of things could go wrong, but my interest (other than classification) is on improving this data structure.</p> <pre><code>template &lt;class K, class V&gt; class Tree { unsigned int depth; Tree* parent; std::vector&lt;Tree&gt; branches; public: K key; V val; int n_trees; Tree(K key = 0, int depth = 0, Tree* parent = 0) : depth(depth), parent(parent), key(key) { val = 0; n_trees = 0; inc(); } void inc() { if (parent) parent-&gt;inc(); n_trees++; } void add(const K* search, const unsigned int length, const V value) { const int index = search[depth]; if (length &lt;= depth) { val = value; return; } for (unsigned int i = 0; i &lt; branches.size(); ++i) { if (branches[i].key == index) { branches[i].add(search, length, value); return; } } branches.push_back( Tree(index, depth + 1, this) ); branches.back().add(search, length, value); } V find(const K* search, const unsigned int length) { const int index = search[depth]; if (length &lt;= depth) { return val; } for (unsigned int i = 0; i &lt; branches.size(); ++i) { if (branches[i].key == index) { return branches[i].find(search,length); } } return 0; // won't work for all types lol } }; </code></pre>

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<blockquote> <p><strong>4.2 Machine Epsilon</strong></p> <p>Find the floating point number epsi that has the the following properties:</p> <ol> <li>1.0+epsi is greater than 1.0 and</li> <li>Let m b e any number less than epsi. Then 1.0+m is equal to 1.0.</li> </ol> <p>epsi is called machine epsilon. It is of great importance in understanding floating point numbers.</p> </blockquote> <p>I have written the following program to try and find my machine epsilon value to a given search depth (10). Do you have any ideas how I could write this program better?</p> <pre><code>(defpackage :find-epsi (:use cl)) (in-package :find-epsi) (defun smaller-scale (&amp;OPTIONAL (epsi 1.0)) (if (&gt; (+ 1.0 epsi) 1.0) (smaller-scale (/ epsi 10)) epsi)) (defun bigger (epsi inc-unit) (if (&lt; (+ 1.0 epsi) 1.0) (bigger (+ epsi inc-unit) inc-unit) epsi)) (defun smaller (epsi dec-unit) (if (&gt; (+ 1.0 epsi) 1.0) (smaller (+ epsi dec-unit) dec-unit) epsi)) (defun find-epsi (&amp;OPTIONAL (search-depth 10) (epsi (smaller-scale)) (incdec-unit epsi)) (if (= search-depth 0) epsi (find-epsi (1- search-depth) (bigger (smaller epsi incdec-unit) incdec-unit) incdec-unit))) (format t "epsi: ~a ~%" (find-epsi)) </code></pre> <p>It seems that it should be much simpler to find epsilon than I originally thought. What do you think about the following program?</p> <pre><code>(defpackage :find-epsi (:use cl)) (in-package :find-epsi) (defun find-epsi (&amp;OPTIONAL (epsi 1.0)) (if (&gt; (+ 1.0 epsi) 1.0) ; if the variable epsi is still significant (find-epsi (/ epsi 2)) ; halve it and try again epsi)) ; otherwise, we have found epsilon (format t "epsi: ~a ~%" (find-epsi)) </code></pre>

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<p>How can I improve this code?</p> <pre><code>public class Address { public string house_no { get; set; } public string street { get; set; } public string zip { get; set; } } public class Contact { public string email { get; set; } public string ph_no { get; set; } public Address address { get; set; } } //Test program class Program { static void GetContacts(string input) { JavaScriptSerializer serializer = new JavaScriptSerializer(); Dictionary&lt;string, Contact&gt; ContactList = serializer.Deserialize&lt;Dictionary&lt;string, Contact&gt;&gt;(input); } static void Main(string[] args) { //jsonText is a string that I retrieve from a web service. string jsonText = ws.GetContactList(); GetContacts(jsonText); } } </code></pre>

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<p>I have a model I have created to generate iCal and the necessary JSON for the jQuery calendar plugin <a href="http://arshaw.com/fullcalendar/">Full Calendar</a> to work. When I display the page, the JSON generation takes about 7 seconds. The query itself has been running in only a few microseconds. So I know my code is the problem. </p> <p>I was trying to get the format like what <a href="http://arshaw.com/fullcalendar/docs/event_data/Event_Object/">Full Calendar expects</a> thus why I wrote the code how I did. My guess is that the below is the problem. Any thoughts on where I can improve this?</p> <pre><code>#region Event public class Event { public string Title { set; get; } public string Description { set; get; } public string URL { set; get; } public string UID { set; get; } public DateTime DateTimeStamp { set; get; } public DateTime CreatedDateTime { set; get; } public DateTime Start { set; get; } public DateTime End { set; get; } public bool AllDay { set; get; } } #endregion public class Calendar { #region Model public string CalendarName { set; get; } public string Product { set; get; } public string TimeZone { set; get; } public List&lt;Event&gt; Events { private set; get; } #endregion /// &lt;summary&gt; /// Creates a calendar json string. /// &lt;/summary&gt; /// &lt;returns&gt;&lt;/returns&gt; public string ToFullCalendarJsonString() { StringBuilder sb = new StringBuilder(); sb.Append("["); int count = Events.Count; int i = 0; foreach (Event eventItem in Events) { sb.Append("{"); sb.AppendFormat("\"title\":\"{0}\",", eventItem.Title); sb.AppendFormat("\"allDay\":\"{0}\",", eventItem.AllDay); if (eventItem.AllDay) { sb.AppendFormat("\"start\":\"{0}T00:00:00\",", eventItem.Start.ToString("yyyy-MM-dd")); sb.AppendFormat("\"end\":\"{0}T00:00:00\",", eventItem.End.ToString("yyyy-MM-dd")); } else { sb.AppendFormat("\"start\":\"{0}T{1}\",", eventItem.Start.ToString("yyyy-MM-dd"), eventItem.Start.ToString("HH:mm:ss")); sb.AppendFormat("\"end\":\"{0}T{1}\",", eventItem.End.ToString("yyyy-MM-dd"), eventItem.End.ToString("HH:mm:ss")); } sb.AppendFormat("\"url\":\"{0}\"", eventItem.URL); sb.Append("}"); i++; if (i &lt; count) { sb.Append(","); } } sb.Append("]"); return sb.ToString(); } </code></pre>

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<p>The below code feels ugly, how can I make it better? (The part i don't like is the ||=. I also don't know if I like the resulting data structure. (An array of hashes)</p> <pre><code>def survey_results @survey_results = [] unless params[:step_survey_id].blank? SurveyResult.find_by_step_survey_id(params[:step_survey_id]).step_survey.step_survey_questions.each do |survey_question| survey_result = {:question =&gt; survey_question.value} answers = {} survey_question.survey_result_answers.each do |survey_result_answer| #Setup initial answer hash with key as the response, only used when needed answers[survey_result_answer.response] ||= 0 answers[survey_result_answer.response] += 1 end survey_result[:answers] = answers @survey_results.push(survey_result) end end end </code></pre>

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<blockquote> <p><strong>3.23 Palindromes</strong></p> <p>A palindrome is a number that reads the same forwards and backwards, like 12321. Write a program that tests input integers for the palindrome property.</p> <p>Hint: This should not be done with the numbers in their input (character) format.</p> </blockquote> <p>For the task above, I have written the following program. Rather than converting the number to a string, I recursively divide the number to create a list of individual digits and then compare the digits from outside to in to determine if it's a palindrome. What do you think of my strategy and of my code in general? I understand that tail recursion is not guaranteed to work in Common Lisp - should I rewrite this code to use loops instead?</p> <pre><code>(defun collect-digits (candidate &amp;OPTIONAL (digit-list ())) ; make a list out of the digits of the number ; example: (= (collect-digits 12321) (1 2 3 2 1)) is true (if (&lt; candidate 10) (cons candidate digit-list) (multiple-value-call (lambda (sub-candidate onesdigit) (collect-digits sub-candidate (cons onesdigit digit-list))) (floor candidate 10)))) (defun reflection-p (candidate-list &amp;OPTIONAL (len (length candidate-list))) ; if c-l[first] = c-l[last] (and (= (car candidate-list) (car (last candidate-list 1))) ; and the list is 3 or smaller ex. (3 1 3), it is a reflection (if (&lt;= len 3) t ; if longer, keep looking (reflection-p (subseq candidate-list 1 (1- len)) (- len 2))))) (defun palindrome-p (candidate) (reflection-p (collect-digits candidate))) (format t "12321: ~a ~%3456789 ~a ~%" (palindrome-p 12321) (palindrome-p 3456789)) </code></pre>

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<p>Typical tutorials suggest simple CoreLocation code similar to the following:</p> <p>Header</p> <pre><code>#import&lt;CoreLocation/CoreLocation.h&gt; @interface MyCLController : NSObject &lt;CLLocationManagerDelegate&gt; { CLLocationManager *locManager; } @property (nonatomic, retain) CLLocationManager *locManager; @end </code></pre> <p>Setup</p> <pre><code>.... self.locManager = [[[CLLocationManager alloc] init] autorelease]; if(!self.locManager.locationServicesEnabled) { NSLog(@"User has opted out of location services"); } self.locManager.delegate = self; self.locManager.desiredAccuracy = kCLLocationAccuracyBest; self.locManager.distanceFilter = 880.0f; // About 1/10th mile, in meters [self.locManager startUpdatingLocation]; .... </code></pre> <p>Methods</p> <pre><code>- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error { // Respond to errors NSLog(@"Location manager error: %@", [error description]); return; } - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation { NSLog(@"%@\n", [newLocation description]); } </code></pre> <p>Deallocate</p> <pre><code>.... [self.locManager release] .... </code></pre> <p>The above code works, but what common problems should I expect once I start testing on the most common iOS devices and versions? (assuming target of iOS 3.2 and above, building on iOS 4.3 SDK, code should work on all iOS devices that support at least 3.2 and any devices that support above 3.2)</p> <p>Many simple examples online are 1-2 years old - are there improvements to the above that should be made due to changes in CoreLocation and the new devices released since 3.2?</p> <p>What other suggestions would make the above more robust, and are there any other pitfalls developers should be aware of as they develop for CoreLocation?</p>

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<p>After growing tired of all the ways in which a file loop can be broken (<code>find -print | while read</code>) or unreadable (<code>find -exec</code> with complex commands), I think I've managed to build a <a href="https://github.com/l0b0/tilde/blob/master/examples/safe-find.sh"><code>find</code> template</a> which can handle <strong>any and all files</strong> which could possibly exist on a Linux system (not so famous last words). Can you find a way to break it, by changing either the <code>test_</code> variables or the environment? For example, is it possible to mess with file descriptor 9 outside the script so that it won't work?</p> <p>The only requirement is "sanity." In other words, <code>test_file_name</code> and <code>test_dir_path</code> cannot contain <code>\0</code> or <code>/</code>, <code>test_file_path</code> cannot contain <code>\0</code> (or be more than 1 level deep, since <code>mkdir</code> for the sake of the test is run without <code>-p</code>), and <code>/bin/bash</code> must be a stable version of Bash 4.</p> <pre><code>#!/bin/bash # Filenames can contain *any* character except only null (\0) and slash (/); # here's some general rules to handle them: # # $'...' can be used to create human readable strings with escape sequences. # # ' -- ' in commands is necessary to separate arguments from filenames, since # filenames can start with '--', and would therefore be handled as parameters. # To handle parameters properly (like GNU tools) use `getopt`. # # `find` doesn't support this syntax, so we use `readlink` to get an absolute # path which by definition starts with slash. # # The "$()" construct strips trailing newlines, so we have to add a different # character and then strip it outside the "$()" construct. # # `IFS=` is necessary to avoid that any characters in IFS are stripped from # the start and end of $path. # # '-r' avoids interpreting backslash in filenames specially. # # '-d '' splits filenames by the null character. # # '-print0' separates find output by null characters. # # Variables inside '$()' have to be quoted just like outside this construct. # # Use process substitution with "&lt;(" instead of pipes to avoid broken pipes. # # Use file descriptor 9 for data storage instead of standard input to avoid # greedy commands like `cat` eating all of it. set -o errexit set -o nounset set -o noclobber test_file_name=$'--$`\! *@ \a\b\e\E\f\r\t\v\\\"\' \n' test_dir_path="$test_file_name" test_file_path="${test_dir_path}/${test_file_name}" mkdir -- "$test_dir_path" touch -- "$test_file_path" absolute_dir_path_x="$(readlink -fn -- "$test_dir_path"; echo x)" absolute_dir_path="${absolute_dir_path_x%x}" exec 9&lt; &lt;( find "$absolute_dir_path" -type f -print0 ) while IFS= read -r -d '' -u 9 do file_path="$(readlink -fn -- "$REPLY"; echo x)" file_path="${file_path%x}" echo "START${file_path}END" done rm -- "$test_file_path" rmdir -- "$test_dir_path" </code></pre>

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<p>I have a section of code I use to extract an event log out of a large text file. It works well, it's just my use of <code>list(itertools.takewhile(...))</code> that feels a little sketchy to me.</p> <p>Is there a nicer way of doing this? </p> <pre><code>import itertools testdata = ''' Lots of other lines... Really quite a few. ************* * Event Log * ************* Col1 Col2 Col3 ----- ----- ----- 1 A B 2 A C 3 B D Other non-relevant stuff... ''' def extractEventLog(fh): fhlines = (x.strip() for x in fh) list(itertools.takewhile(lambda x: 'Event Log' not in x, fhlines)) list(itertools.takewhile(lambda x: '-----' not in x, fhlines)) lines = itertools.takewhile(len, fhlines) # Event log terminated by blank line for line in lines: yield line # In the real code, it's parseEventLogLine(line) </code></pre> <p>Expected output:</p> <pre><code>&gt;&gt;&gt; list(extractEventLog(testdata.splitlines())) ['1 A B', '2 A C', '3 B D'] </code></pre>

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<p>I figured it's about time to jump into some Haskell, so here's a first attempt at an oddly specific SVG parser:</p> <pre><code>import System.Environment import Text.ParserCombinators.Parsec parseFile fname = parseFromFile (manyTill (try tag) (try readEnd)) fname tag = do manyTill anyChar . try $ lookAhead tagStart char '&lt;' name &lt;- many $ noneOf " " props &lt;- tagContents char '&gt;' junk return (name, props) tagContents = do props &lt;- manyTill property . try . lookAhead $ char '&gt;' junk return props property = do spaces name &lt;- many1 $ noneOf "=" string "=\"" val &lt;- manyTill anyChar $ char '"' junk return (name, val) junk = optional . many $ oneOf "\n\r\t\\/" readEnd = do optional $ string "&lt;/svg&gt;" junk eof tagStart = do char '&lt;' tagName tagName = string "rect" &lt;|&gt; string "polygon" &lt;|&gt; string "polyline" &lt;|&gt; string "circle" &lt;|&gt; string "path" &lt;|&gt; string "g" &lt;|&gt; string "svg" </code></pre> <p>Before anyone asks, one of the objectives for this program (other than learning) is that it should accept invalid SVGs (for example, a partial SVG or one that has been saved as an <code>rtf</code>), which is why I'm making liberal use of <code>try</code>, and cherry-picking tags.</p> <p>As implied by the title, this is my first non-tutorial attempt at Haskell, so give me all the style pointers you can muster (and highlight anything that signals a broken understanding on my part).</p> <p>I'd also appreciate pointers on how to cherry-pick properties (and not just tags). I've tried writing <code>property</code> as </p> <pre><code>property = do manyTill anyChar . try $ lookAhead tagName name &lt;- many1 $ noneOf "=" string "=\"" val &lt;- manyTill anyChar $ char '"' junk return (name, val) </code></pre> <p>and defining <code>propName</code> as </p> <pre><code>propName = string "points" &lt;|&gt; string "x" &lt;|&gt; string "y" &lt;|&gt; string "r" &lt;|&gt; string "d" &lt;|&gt; string "cx" &lt;|&gt; string "cy" &lt;|&gt; string "width" &lt;|&gt; string "height" &lt;|&gt; string "transform" </code></pre> <p>This seems like it should work since it's basically how I got <code>tag</code> jumping to the next desired tag, but it gives me unexpected input errors.</p> <hr> <p>Edit The Second:</p> <pre><code>import System.Environment import Text.ParserCombinators.Parsec type TagName = String type Property = (PropName, Value) type PropName = String type Value = String parseFile fname = parseFromFile (manyTill (try tag) (try readEnd)) fname tag :: GenParser Char st (TagName, [Property]) tag = do manyTill anyChar . try $ lookAhead tagStart name &lt;- tagStart props &lt;- tagContents char '&gt;' junk return (name, props) tagContents :: GenParser Char st [Property] tagContents = do props &lt;- manyTill property . try . lookAhead $ char '&gt;' junk return props property :: GenParser Char st (PropName, Value) property = do manyTill anyChar . try $ lookAhead propName name &lt;- many1 $ noneOf "=" string "=\"" val &lt;- manyTill anyChar $ char '"' junk return (name, val) junk = many $ oneOf "\n\r\t\\/{} " tagStart :: GenParser Char st TagName tagStart = do char '&lt;' name &lt;- tagName return name readEnd = do optional $ string "&lt;/svg&gt;" junk eof tagName = oneStringOf ["rect", "polygon", "polyline", "circle", "path", "g", "svg"] propName = oneStringOf ["points", "x", "y", "r", "d", "cx", "cy", "width", "height", "transform"] oneStringOf :: [String] -&gt; GenParser Char st String oneStringOf = choice . map (try . string) </code></pre> <ul> <li>Added <code>try</code> to the definition of <code>oneStringOf</code></li> </ul>

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<p>The idea here is to implement a simple, threadsafe, observable collection that clients can bind to, whilst background threads can update. Changes in the contained items raise the <code>CollectionChanged</code> event. </p> <p>Feedback appreciated:</p> <pre><code>public class ThreadSafeObservableCollection&lt;T&gt; : INotifyCollectionChanged where T: INotifyPropertyChanged { private readonly Object _lock = new Object(); private readonly Collection&lt;T&gt; _items = new Collection&lt;T&gt;(); private ReadOnlyCollection&lt;T&gt; _readonlyItems; public ThreadSafeObservableCollection() { } public ThreadSafeObservableCollection(IEnumerable&lt;T&gt; items) { _items = new ObservableCollection&lt;T&gt;(items); foreach (T item in _items) { ((INotifyPropertyChanged) item).PropertyChanged += ItemPropertyChangedHandler; } } public ReadOnlyCollection&lt;T&gt; Items { get { return _readonlyItems ?? (_readonlyItems = new ReadOnlyCollection&lt;T&gt;(_items)); } } public virtual void Add(T obj) { lock(_lock) { ((INotifyPropertyChanged) obj).PropertyChanged += ItemPropertyChangedHandler; _items.Add(obj); OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, obj)); } } public virtual void Remove(T obj) { lock (_lock) { ((INotifyPropertyChanged) obj).PropertyChanged -= ItemPropertyChangedHandler; _items.Remove(obj); OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, obj)); } } #region INotify Members public event NotifyCollectionChangedEventHandler CollectionChanged; protected virtual void OnCollectionChanged(NotifyCollectionChangedEventArgs args) { var copy = CollectionChanged; if(copy != null) { CollectionChanged(this, args); } } private void ItemPropertyChangedHandler(object sender, PropertyChangedEventArgs e) { NotifyCollectionChangedEventArgs args = new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset); OnCollectionChanged(args); } #endregion } </code></pre> <p><strong>Update</strong></p> <p>In response to the comments about the ReadOnlyCollection, I have switch its implementation for a yield block that is locked (Using a ReaderWriterLock) for the length of the enumeration, like so:</p> <pre><code> public IEnumerable&lt;T&gt; Items { get { _lock.AcquireReaderLock(_lockTimeout); try { foreach (T item in _items) { yield return item; } } finally { _lock.ReleaseReaderLock(); } } } </code></pre> <p>Any thoughts?</p>

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<p>How can this code be improved?</p> <pre><code>using System; //using System.Linq; using System.Collections; using System.Collections.Generic; namespace Combinatorics { public class Permutation { private int[] data = null; private int order = 0; public Permutation(int n) { this.data = new int[n]; for (int i = 0; i &lt; n; ++i) { this.data[i] = i; } this.order = n; } public Permutation(int n, int k) { this.data = new int[n]; this.order = this.data.Length; // Step #1 - Find factoradic of k int[] factoradic = new int[n]; for (int j = 1; j &lt;= n; ++j) { factoradic[n - j] = k % j; k /= j; } // Step #2 - Convert factoradic to permuatation int[] temp = new int[n]; for (int i = 0; i &lt; n; ++i) { temp[i] = ++factoradic[i]; } this.data[n - 1] = 1; // right-most element is set to 1. for (int i = n - 2; i &gt;= 0; --i) { this.data[i] = temp[i]; for (int j = i + 1; j &lt; n; ++j) { if (this.data[j] &gt;= this.data[i]) ++this.data[j]; } } for (int i = 0; i &lt; n; ++i) // put in 0-based form { --this.data[i]; } } // Permutation(n,k) private Permutation(int[] a) { this.data = new int[a.Length]; a.CopyTo(this.data, 0); this.order = a.Length; } public int Order { get { return this.order; } } public Object[] ApplyTo(Object[] arr) { Object[] result = new Object[arr.Length]; for (int i = 0; i &lt; result.Length; ++i) { result[i] = arr.GetValue(this.data[i]); } return result; } public Permutation Next() { Permutation result = new Permutation(this.order); int left, right; for (int k = 0; k &lt; result.order; ++k) // Step #0 - copy current data into result { result.data[k] = this.data[k]; } left = result.order - 2; // Step #1 - Find left value while ((result.data[left] &gt; result.data[left + 1]) &amp;&amp; (left &gt;= 1)) { --left; } if ((left == 0) &amp;&amp; (this.data[left] &gt; this.data[left + 1])) return null; right = result.order - 1; // Step #2 - find right; first value &gt; left while (result.data[left] &gt; result.data[right]) { --right; } int temp = result.data[left]; // Step #3 - swap [left] and [right] result.data[left] = result.data[right]; result.data[right] = temp; int i = left + 1; // Step #4 - order the tail int j = result.order - 1; while (i &lt; j) { temp = result.data[i]; result.data[i++] = result.data[j]; result.data[j--] = temp; } return result; } public Permutation Element(int n) { int[] result = new int[data.Length]; int[] factoradic = new int[data.Length]; // Find the factoradic for (int i = 1; i &lt;= data.Length; i++) { factoradic[data.Length - i] = n % i; n /= i; } // Convert the factoradic to the permutation IList&lt;int&gt; tempList = new List&lt;int&gt;(data); for (int i = 0; i &lt; data.Length; i++) { result[i] = tempList[factoradic[i]]; tempList.RemoveAt(factoradic[i]); } return new Permutation(result); } public Permutation this[int n] { get { return this.Element(n); } } public static ArrayList Generate(Object[] list, bool random) { Permutation p = new Permutation(list.Length); ArrayList result = new ArrayList(); if (random){ int permNum = new Random().Next(Util.Factorial(list.Length)); result.Add( p[permNum].ApplyTo(list)); } else { while (p != null) { result.Add(p.ApplyTo(list)); p = p.Next(); } } return result; } } public class Combination { private int n = 0; private int k = 0; private int[] data = null; public Combination(int n, int k) { this.n = n; this.k = k; this.data = new int[k]; for (int i = 0; i &lt; k; ++i) this.data[i] = i; } // Combination(n,k) public Combination(int n, int k, int[] a) // Combination from a[] { this.n = n; this.k = k; this.data = new int[k]; for (int i = 0; i &lt; a.Length; ++i) this.data[i] = a[i]; } // Combination(n,k,a) public bool IsValid() { if (this.data.Length != this.k) return false; // corrupted for (int i = 0; i &lt; this.k; ++i) { if (this.data[i] &lt; 0 || this.data[i] &gt; this.n - 1) return false; // value out of range for (int j = i + 1; j &lt; this.k; ++j) if (this.data[i] &gt;= this.data[j]) return false; // duplicate or not lexicographic } return true; } // IsValid() public Combination Next() { if (this.data[0] == this.n - this.k) return null; Combination ans = new Combination(this.n, this.k); int i; for (i = 0; i &lt; this.k; ++i) ans.data[i] = this.data[i]; for (i = this.k - 1; i &gt; 0 &amp;&amp; ans.data[i] == this.n - this.k + i; --i) ; ++ans.data[i]; for (int j = i; j &lt; this.k - 1; ++j) ans.data[j + 1] = ans.data[j] + 1; return ans; } // Successor() public Combination First() { Combination ans = new Combination(this.n, this.k); for (int i = 0; i &lt; ans.k; ++i) ans.data[i] = i; return ans; } // First() public Object[] ApplyTo(Array arr) { Object[] result = new Object[arr.Length]; for (int i = 0; i &lt; result.Length; ++i) { result[i] = arr.GetValue(this.data[i]); } return result; } public Object[] ApplyTo(Object[] strarr) { Object[] result = new Object[this.k]; for (int i = 0; i &lt; result.Length; ++i) result[i] = strarr[this.data[i]]; return result; } // ApplyTo() public static int Choose(int n, int k) { if (n &lt; k) return 0; // special case if (n == k) return 1; int delta, iMax; if (k &lt; n - k) // ex: Choose(100,3) { delta = n - k; iMax = k; } else // ex: Choose(100,97) { delta = k; iMax = n - k; } int ans = delta + 1; for (int i = 2; i &lt;= iMax; ++i) { checked { ans = (ans * (delta + i)) / i; } // Throws OverFlow Exception } return ans; } // Choose() // return the mth lexicographic element of combination C(n,k) public Combination Element(int m) { int[] ans = new int[this.k]; int a = this.n; int b = this.k; int x = (Choose(this.n, this.k) - 1) - m; // x is the "dual" of m for (int i = 0; i &lt; this.k; ++i) { ans[i] = LargestV(a, b, x); // largest value v, where v &lt; a and vCb &lt; x x = x - Choose(ans[i], b); a = ans[i]; b = b - 1; } for (int i = 0; i &lt; this.k; ++i) { ans[i] = (n - 1) - ans[i]; } return new Combination(this.n, this.k, ans); } // Element() public Combination this[int m] { get { return this.Element(m); } } // return largest value v where v &lt; a and Choose(v,b) &lt;= x private static int LargestV(int a, int b, int x) { int v = a - 1; while (Choose(v, b) &gt; x) --v; return v; } // LargestV() public static ArrayList Generate(Object[] list, int choose, bool random) { Combination c = new Combination(list.Length, choose); ArrayList result = new ArrayList(); if (random) { int permNum = new Random().Next(Util.Combination(list.Length, choose)); result.Add(c[permNum].ApplyTo(list)); } else { while (c != null) { result.Add(c.ApplyTo(list)); c = c.Next(); } } return result; } } public class Variation { //public static IEnumerable&lt;IEnumerable&lt;T&gt;&gt; CartesianProduct&lt;T&gt;(this IEnumerable&lt;IEnumerable&lt;T&gt;&gt; sequences) //{ // IEnumerable&lt;IEnumerable&lt;T&gt;&gt; emptyProduct = new[] { Enumerable.Empty&lt;T&gt;() }; // return sequences.Aggregate( // emptyProduct, // (accumulator, sequence) =&gt; // from accseq in accumulator // from item in sequence // select accseq.Concat(new[] { item })); //} public static ArrayList Generate(Object[][] lists) { int seqCount = lists.Length; ArrayList accum = new ArrayList(seqCount); if (seqCount &gt; 0) { Stack enumStack = new Stack(); Stack itemStack = new Stack(); int index = seqCount - 1; IEnumerator enumerator = lists[index].GetEnumerator(); while (true) if (enumerator.MoveNext()) { itemStack.Push(enumerator.Current); if (index == 0) { accum.Add(itemStack.ToArray()); itemStack.Pop(); } else { enumStack.Push(enumerator); enumerator = lists[--index].GetEnumerator(); } } else { if (++index == seqCount) break; itemStack.Pop(); enumerator = enumStack.Pop() as IEnumerator; } } return accum; } } public class Util { public static int Factorial(int n) { int f = 1; while (n &gt; 1) { f *= n; --n; } return f; } public static int Combination(int n, int k) { return Factorial(n) / (Factorial(k) * Factorial(n - k)); } } } </code></pre>

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<p>The following block of code needs to be as fast as possible as it likely to be called many thousands of times in a run.</p> <p>I am also conscious that my thinking style is leaning towards a more procedural style from time to time and hence I may not be taking full advantage of all the benefits that functional programming brings.</p> <p>Any tips for</p> <ol> <li>making the code run faster, and</li> <li>making it more functional</li> </ol> <p></p> <pre><code>let qarray (tableName : string) (startAge : int) (startYear : int) = let tableData = File.ReadAllLines tableName // find which row the vertex is in let vrow = Array.findIndex (fun (s:string) -&gt; s.StartsWith vertexLiteral) tableData let firstYear = int(tableData.[vrow].Split('\t').[1]) // filter out all the row prior to the column headers e.g. table description and comments let filteredArray = Array.sub tableData (vrow+1) (tableData.Length-vrow-1) // use the vertex info to read all lines beyond that, converting to doubles let f (s:string) = s.Split('\t') |&gt; Array.map double let fullArray = Array.map f filteredArray [| for i in 0 .. (120 - startAge - 1) -&gt; fullArray.[startAge + i - 1].[System.Math.Min(startYear - firstYear + i + 1, fullArray.[0].Length)] |] </code></pre>

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<p>I'm working on my graduate project and I had stumbled upon a somewhat dilemma, I've managed to solve it with some workarounds but I have my doubts that this is the most efficient way to deal with this problem.</p> <p>I'm writing a class to deal with the Plesk API and making it as flexible as possible for easy use.</p> <p>Here is the function for generating the XML that will be send out as request: </p> <pre><code>private function emailCreatePacket($domain, $params){ // Create new XML document. $xml = new DomDocument('1.0', 'UTF-8'); $xml-&gt;formatOutput = true; // Create packet $packet = $xml-&gt;createElement('packet'); $packet-&gt;setAttribute('version', '1.4.2.0'); $xml-&gt;appendChild($packet); $mail = $xml-&gt;createElement('mail'); $packet-&gt;appendChild($mail); $create = $xml-&gt;createElement('create'); $mail-&gt;appendChild($create); $filter = $xml-&gt;createElement('filter'); $create-&gt;appendChild($filter); $domain_id = $xml-&gt;createElement('domain_id', $domain-&gt;id); $filter-&gt;appendChild($domain_id); $mailname = $xml-&gt;createElement('mailname'); $filter-&gt;appendChild($mailname); foreach ($params as $key =&gt; $value) { $node = $mailname; if(strpos($key, ':') !== false){ $split = explode(':', $key); $key = $split[1]; $node = ${$split[0]}; if(!isset(${$split[0]})){ ${$split[0]} = $xml-&gt;createElement($split[0]); $mailname-&gt;appendChild(${$split[0]}); } $xmlelement = $xml-&gt;createElement($key, $value); ${$split[0]}-&gt;appendChild($xmlelement); }else{ $xmlelement = $xml-&gt;createElement($key, $value); $node-&gt;appendChild($xmlelement); } } return $xml-&gt;saveXML(); } </code></pre> <p>Here's my public function:</p> <pre><code>public function createEmail($host, $domain, $params){ $curl = $this-&gt;curlInit($host); $packet = $this-&gt;emailCreatePacket($domain, $params); echo $packet; $response = $this-&gt;sendRequest($curl, $packet); echo $response; if($this-&gt;parseResponse($response)){ return true; } } </code></pre> <p>Here are the functions called:</p> <pre><code>private function curlInit($host) { $security = new Security(); $password = $security-&gt;decode($host['host_pass']); $curl = curl_init(); curl_setopt($curl, CURLOPT_URL, "https://{$host['host_address']}:{$host['host_port']}/{$host['host_path']}"); curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); curl_setopt($curl, CURLOPT_POST, true); curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false); curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false); curl_setopt($curl, CURLOPT_HTTPHEADER, array("HTTP_AUTH_LOGIN: {$host['host_user']}", "HTTP_AUTH_PASSWD: {$password}", "HTTP_PRETTY_PRINT: TRUE", "Content-Type: text/xml") ); return $curl; } private function sendRequest($curl, $packet){ curl_setopt($curl, CURLOPT_POSTFIELDS, $packet); $result = curl_exec($curl); if (curl_errno($curl)) { $error = curl_error($curl); $errorcode = curl_errno($curl); curl_close($curl); throw new Exception("Er is iets mis gegaan: &lt;br /&gt;&lt;br /&gt; Foutcode: " . $errorcode . "&lt;br /&gt; Foutmelding: " . $error ); } curl_close($curl); return $result; } private function parseResponse($response){ $xml = new SimpleXMLElement($response); $status = $xml-&gt;xpath('//status'); if($status[0] == "error"){ $errorcode = $xml-&gt;xpath('//errcode'); $errortext = $xml-&gt;xpath('//errtext'); throw new Exception("Er is iets mis gegaan: &lt;br /&gt;&lt;br /&gt; Foutcode: ". $errorcode[0] . "&lt;br /&gt; Foutmelding: " . $errortext[0]); }else{ return $response; } } </code></pre> <p>Here is the code I use to call my function:</p> <pre><code>&lt;?php /** * @author Jeffro * @copyright 2011 */ require('init.php'); $security = new Security(); if($security-&gt;sslactive()){ try { $hosts = new Hosts(); $host = $hosts-&gt;getHost("192.168.1.60"); $pleskapi = new PleskApi(); $client = $pleskapi-&gt;getClientInfo($host, 'janbham'); $domain = $pleskapi-&gt;getDomainInfo($host, "lol.nl"); $params = array('name' =&gt; 'ohecht', 'mailbox:enabled' =&gt; 'true', 'mailbox:quota' =&gt; '100000000', 'alias' =&gt; 'aapjesrollen', 'password' =&gt; 'testmail', 'permissions:manage_drweb' =&gt; 'true'); $pleskapi-&gt;createEmail($host, $domain, $params); } catch (Exception $ex) { echo $ex-&gt;GetMessage(); } }else{ ?&gt; SSL needs to be active &lt;?php } ?&gt; </code></pre> <p>The problem was regarding the structure the API uses with it deeper nesting every time (which I solved now using ':' as a delimiter)</p>

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<p>While working with DirectShow, I came across the need to easily recognize different known 'sets' of GUIDs. E.g.: There are different GUIDs to indicate the possible time formats: <code>None, Byte, Field, Frame, MediaTime, Sample</code>. Working with enums instead of GUIDs would be a lot more useful in my opinion.</p> <p>I decided to write the following abstract wrapper class which allows linking GUIDs to enums. You need to extend from it with the enum you want to expose as a type parameter.</p> <pre><code>/// &lt;summary&gt; /// An abstract class to represent a set of GUIDs as an enum. /// &lt;/summary&gt; /// &lt;typeparam name="T"&gt;An enum to use for the type to expose.&lt;/typeparam&gt; abstract class AbstractGuidEnum&lt;T&gt; { /// &lt;summary&gt; /// The internal GUID. /// &lt;/summary&gt; public Guid Guid { get; private set; } /// &lt;summary&gt; /// The enum type for this GUID. /// &lt;/summary&gt; public T Type { get; private set; } /// &lt;summary&gt; /// Specifies whether the GUID is known as a specific type or not. /// &lt;/summary&gt; public bool IsKnownType { get; private set; } /// &lt;summary&gt; /// List matching GUIDs with the enum types. /// &lt;/summary&gt; private static Dictionary&lt;Guid, T&gt; m_typeList; /// &lt;summary&gt; /// Create a new GUID enum wrapping the given GUID. /// &lt;/summary&gt; /// &lt;param name="guid"&gt;&lt;/param&gt; protected AbstractGuidEnum( Guid guid ) { Guid = guid; if ( IsGuidKnownType( guid ) ) { IsKnownType = true; Type = GetType( guid ); } else { IsKnownType = false; } } /// &lt;summary&gt; /// Create a new GUID enum for the specified type. /// &lt;/summary&gt; /// &lt;param name="type"&gt;&lt;/param&gt; protected AbstractGuidEnum( T type ) { Type = type; Guid = GetGuid( type ); } /// &lt;summary&gt; /// Call to make sure the list of types is initialized. /// &lt;/summary&gt; private void InitializeTypes() { if ( m_typeList == null ) { m_typeList = new Dictionary&lt;Guid, T&gt;(); FillTypeList( m_typeList ); } } public bool IsGuidKnownType( Guid guid ) { InitializeTypes(); return m_typeList.ContainsKey( guid ); } /// &lt;summary&gt; /// Returns the type for a given GUID. /// &lt;/summary&gt; /// &lt;param name="type"&gt;The GUID to get the type for.&lt;/param&gt; /// &lt;returns&gt;The type for the given GUID.&lt;/returns&gt; public T GetType( Guid type ) { InitializeTypes(); if ( !m_typeList.ContainsKey( type ) ) { throw new ArgumentException("No type is defined for the given GUID.", "type"); } return m_typeList[ type ]; } /// &lt;summary&gt; /// Return the guid for a given type. /// &lt;/summary&gt; /// &lt;param name="type"&gt;The Type to get the Guid for.&lt;/param&gt; /// &lt;returns&gt;The Guid for the given type.&lt;/returns&gt; /// &lt;exception cref="InvalidCastException"&gt; /// Thrown when no Guid exists for the given type. /// &lt;/exception&gt; private Guid GetGuid( T type ) { InitializeTypes(); try { return m_typeList.Keys.First( guid =&gt; m_typeList[ guid ].Equals( type ) ); } catch ( InvalidOperationException ) { throw new InvalidCastException( "No Guid exists for the given type." ); } } public override bool Equals( object obj ) { if ( !(obj is AbstractGuidEnum&lt;T&gt;) ) { return false; } AbstractGuidEnum&lt;T&gt; guidObj = obj as AbstractGuidEnum&lt;T&gt;; return Guid.Equals( guidObj.Guid ); } public override int GetHashCode() { unchecked { return Guid.GetHashCode(); } } /// &lt;summary&gt; /// Fill up the list which matches GUIDs to the desired enum types. /// &lt;/summary&gt; /// &lt;param name="typeList"&gt;&lt;/param&gt; protected abstract void FillTypeList(Dictionary&lt;Guid, T&gt; typeList); } </code></pre> <p>As an example, the time formats:</p> <pre><code>/// &lt;summary&gt; /// The possible time formats for seeking operations. /// &lt;/summary&gt; public enum TimeFormat { None, Byte, Field, Frame, MediaTime, Sample } /// &lt;summary&gt; /// A wrapper class which represents the possible media types for DirectShow. /// Since a MediaType is a Guid, a simple enum couldn't be used. /// &lt;/summary&gt; class GuidTimeFormat : AbstractGuidEnum&lt;TimeFormat&gt; { /// &lt;summary&gt; /// Create a new GuidTimeFormat wrapping the given GUID. /// &lt;/summary&gt; /// &lt;param name="guid"&gt;The GUID to wrap.&lt;/param&gt; public GuidTimeFormat( Guid guid ) : base( guid ) { } public GuidTimeFormat( TimeFormat timeFormat ) : base( timeFormat ) { } protected override void FillTypeList( Dictionary&lt;Guid, TimeFormat&gt; typeList ) { typeList.Add( DirectShowLib.TimeFormat.None, TimeFormat.None ); typeList.Add( DirectShowLib.TimeFormat.Byte, TimeFormat.Byte ); typeList.Add( DirectShowLib.TimeFormat.Field, TimeFormat.Field ); typeList.Add( DirectShowLib.TimeFormat.Frame, TimeFormat.Frame ); typeList.Add( DirectShowLib.TimeFormat.MediaTime, TimeFormat.MediaTime ); typeList.Add( DirectShowLib.TimeFormat.Sample, TimeFormat.Sample ); } } </code></pre> <p>Plain and simple, but is this the cleanest approach? Any improvements, or reasons why this would be unnecessary?</p> <p>E.g.: Notice that some candidate static functions can't be made static because of <code>InitializeTypes</code> which relies on the overridable <code>FillTypeList</code> method.</p> <hr> <p>So far I agree with most of the comments made, I posted this code since I felt it might be 'inappropriately clever code'. One of the benefits, in a possible scenario is the following however:</p> <pre><code>// Add the found type to the list. MediaType type = new MediaType { MajorType = new GuidMediaMajorType(amType.majorType), SubType = new GuidMediaSubType(amType.subType) }; break; </code></pre> <p>The types are 'wrapped' in the guid type, which tries to link them up to the correct enum, <strong>when found</strong>. The alternative would be to map unknown types to an 'Unknown' enum value, but then the guid information is lost. This does seem to be the only benefit of this wrapper over a simple helper class with conversion functions. By writing this code I actually managed to find <a href="http://sourceforge.net/tracker/?func=detail&amp;aid=3014857&amp;group_id=136334&amp;atid=735691">a copy/paste bug in DirectShowLib</a>, as duplicate GUIDs were declared. Ofcourse, I would have also found this using a simple dictionary approach.</p>

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<p>Given the following problem:</p> <pre><code>;3.3 Tabulate the function k = 2^n for n = 1..50. ;Do this for the fewest possible multiplications.[3] </code></pre> <p>I wrote this answer:</p> <pre><code>(defun k (n) (ash 2 (1- n))) (loop for n from 1 to 50 do (format t "k(~a) = ~a ~%" n (k n))) </code></pre> <p>What do you think?</p>

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<p>Given the following problem:</p> <blockquote> <p>It is conjectured that for any \$n &gt; 0\$, \$n^2 + 3n + 5\$ is never divisible by 121. Test this conjecture for \$n = 1,2,...,9999,10000\$.</p> </blockquote> <p>I wrote the following solution:</p> <pre><code>(defpackage :one-twenty-one-divisible (:use :cl)) (in-package :one-twenty-one-divisible) (defun divisible (n) (= (mod n 121) 0)) (defun f_n (n) (+ (expt n 2) (* 3 n) 5)) (let ((divisible-result (loop for n from 1 to 10000 when (divisible (f_n n)) collect n))) (format t "The conjecture that for 1 &lt;= n &lt;= 10,000 f(n) = n^2 + 3n + 5 is indivisible by 121 is ~:[false~;true~].~%" (null divisible-result)) (unless (null divisible-result) (format t "The following items were found to have f(n) that is divisible by 121: ~a ~%" divisible-result))) </code></pre> <p>What do you think?</p>

1375

<p>I have successfully placed multiple jquery ui slider on a page and its transalation text too. you can check it live on: <a href="http://outsourcingnepal.com/projects/jQuery%20slider/" rel="nofollow">http://outsourcingnepal.com/projects/jQuery%20slider/</a></p> <p>I have my jquery code as :</p> <pre><code>var arrLabel1 = new Array('Not Good', 'OK', 'Average', 'Above Average', 'Excellent', 'Outstanding'); $(function() { $( ".slider_control" ).slider({ value:0, min: 0, max: 5, step: 1, slide: function( event, ui ) { $( "#slider_" + $(this).attr('rel') ).val( ui.value ); $( "#label_" + $(this).attr('rel') ).text( arrLabel1[ ui.value ] ); } }).each(function(index){ $( "#slider_" + (index + 1) ).val( $( this ).slider( "value" ) ); $( "#label_" + (index + 1) ).text( arrLabel1[ $(this).slider( "value" ) ] ); }); }); </code></pre> <p>Now i would like to optimize it so that i can be independent of rel attribute.</p> <p>MY HTML:</p> <pre><code>&lt;ul class="slider-container"&gt; &lt;li class="ui_slider"&gt; &lt;div class="title"&gt;Overall: &lt;span id="label_1"&gt;&lt;/span&gt;&lt;/div&gt; &lt;input type="hidden" name="overall_review" id="slider_1" /&gt; &lt;div class="slider_control" rel="1"&gt;&lt;/div&gt; &lt;/li&gt; &lt;li class="ui_slider"&gt; &lt;div class="title"&gt;Cleanliness: &lt;span id="label_2"&gt;&lt;/span&gt;&lt;/div&gt; &lt;input type="hidden" name="overall_review" id="slider_2" /&gt; &lt;div class="slider_control" rel="2"&gt;&lt;/div&gt; &lt;/li&gt; &lt;li class="ui_slider"&gt; &lt;div class="title"&gt;Facilities: &lt;span id="label_3"&gt;&lt;/span&gt;&lt;/div&gt; &lt;input type="hidden" name="overall_review" id="slider_3" /&gt; &lt;div class="slider_control" rel="3"&gt;&lt;/div&gt; &lt;/li&gt; &lt;li class="ui_slider"&gt; &lt;div class="title"&gt;Location: &lt;span id="label_4"&gt;&lt;/span&gt;&lt;/div&gt; &lt;input type="hidden" name="overall_review" id="slider_4" /&gt; &lt;div class="slider_control" rel="4"&gt;&lt;/div&gt; &lt;/li&gt; &lt;li class="ui_slider"&gt; &lt;div class="title"&gt;Quality of Service: &lt;span id="label_5"&gt;&lt;/span&gt;&lt;/div&gt; &lt;input type="hidden" name="overall_review" id="slider_5" /&gt; &lt;div class="slider_control" rel="5"&gt;&lt;/div&gt; &lt;/li&gt; &lt;li class="ui_slider"&gt; &lt;div class="title"&gt;Room: &lt;span id="label_6"&gt;&lt;/span&gt;&lt;/div&gt; &lt;input type="hidden" name="overall_review" id="slider_6" /&gt; &lt;div class="slider_control" rel="6"&gt;&lt;/div&gt; &lt;/li&gt; &lt;li class="ui_slider"&gt; &lt;div class="title"&gt;Value of Money: &lt;span id="label_7"&gt;&lt;/span&gt;&lt;/div&gt; &lt;input type="hidden" name="overall_review" id="slider_7" /&gt; &lt;div class="slider_control" rel="7"&gt;&lt;/div&gt; &lt;/li&gt; &lt;/ul&gt; </code></pre>

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<p>I've written a plugin that takes a generic approach to creating sticky headers and would like to have the code reviewed. Is this acceptable JavaScript?</p> <p><strong><a href="http://robertfall.github.com/Stuck-On-Top/" rel="nofollow">Demo Page</a></strong></p> <p>It's my first plugin however and I'd like feedback about how to make it more user friendly and more readable before releasing it and putting it up on GitHub.</p> <p>The header becomes stuck to the top of the page until it encounters the bottom of it's container, upon which it gets stuck to the bottom of the container and floats off the screen.</p> <p>I had to create a placeholder to take the header's original place once it leaves the document flow and also apply fixed CSS settings to the header to keep it's appearance the same when it leaves the flow.</p> <pre><code>(function ($) { $.fn.stickySectionHeaders = function (options) { var settings = $.extend({ stickyClass: 'header', padding: 0 }, options); return $(this).each(function () { var container = $(this); var header = $('.' + settings.stickyClass, container); var originalCss = { position: header.css('position'), top: header.css('top'), width: header.css('width') }; var placeholder = undefined; var originalWidth = header.outerWidth(); $(window).scroll(function () { var containerTop = container.offset().top; var headerOrigin = header.offset().top; var headerHeight = header.outerHeight(); var containerHeight = container.outerHeight(); var containerTop = container.offset().top; var containerSize = container.outerHeight(); var pageOffset = $(window).scrollTop() + settings.padding; var containerBottom = containerHeight + containerTop; if (pageOffset &lt; containerTop &amp;&amp; placeholder != undefined) { if (placeholder != undefined) { placeholder.remove(); placeholder = undefined; header.css(originalCss); } } else if (pageOffset &gt; containerTop &amp;&amp; pageOffset &lt; (containerBottom - headerHeight)) { if (placeholder == undefined) { placeholder = $('&lt;div/&gt;') .css('height', header.outerHeight() + 'px') .css('width', header.width() + 'px'); header.before(placeholder); header.css('position', 'fixed'); header.css('width', originalWidth + 'px'); } header.css('top', settings.padding + 'px'); } else if (pageOffset &gt; (containerBottom - headerHeight)) { header.css('top', (containerBottom - headerHeight) - pageOffset + settings.padding + 'px'); } }); }); } })(jQuery); </code></pre>

1381

<p>I have been a programmer for 12 years, mainly ERP software and C development and am looking to make a career/specialty change to Java. I've read it countless times if you want to learn a new language you need to write code, then write some more code and then finally write more code. So I've written some code!</p> <p>I love Poker, so I have written a small Texas Hold'em program. Here is the overview of what it does:</p> <ol> <li>Asks the user for the number of players </li> <li>Create a deck of cards </li> <li>Shuffle </li> <li>Cut the deck </li> <li>Deal players hole cards </li> <li>Burns a card </li> <li>Deals flop </li> <li>Burns a card </li> <li>Deals turn </li> <li>Burns a card </li> <li>Deals river </li> <li>Prints the deck to console to show random deck was used </li> <li>Prints the 'board' </li> <li>Prints burn cards </li> <li>Printers players cards </li> <li>Evaluates the value of each players hand (Royal flush, full house, etc...) </li> </ol> <p>There are 6 .java files (see below for links). I used an interface, created my own comparators, even implemented some try/catch blocks (although I'm still learning how to use these properly).</p> <pre><code>import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; public class TexasHoldEm { public static void main(String[] args) throws Exception { // variables Deck holdemDeck = new Deck(); int numPlayers = 0; int cardCounter = 0; int burnCounter = 0; int boardCounter = 0; Board board = new Board(); // initializations numPlayers = getNumberOfPlayers(); Player[] player = new Player[numPlayers]; /* 3 shuffles just like in real life. */ for(int i=0;i&lt;3;i++){ holdemDeck.shuffle(); } // Cut Deck holdemDeck.cutDeck(); // Initialize players for (int i=0;i&lt;numPlayers;i++){ player[i] = new Player(); } // Main processing // Deal hole cards to players for (int i=0;i&lt;2;i++){ for (int j=0;j&lt;numPlayers;j++){ player[j].setCard(holdemDeck.getCard(cardCounter++), i); } } // Start dealing board // Burn one card before flop board.setBurnCard(holdemDeck.getCard(cardCounter++), burnCounter++); // deal flop for (int i=0; i&lt;3;i++){ board.setBoardCard(holdemDeck.getCard(cardCounter++), boardCounter++); } // Burn one card before turn board.setBurnCard(holdemDeck.getCard(cardCounter++), burnCounter++); // deal turn board.setBoardCard(holdemDeck.getCard(cardCounter++), boardCounter++); // Burn one card before river board.setBurnCard(holdemDeck.getCard(cardCounter++), burnCounter++); // deal river board.setBoardCard(holdemDeck.getCard(cardCounter++), boardCounter++); //------------------------ // end dealing board //------------------------ System.out.println("The hand is complete...\n"); // print deck holdemDeck.printDeck(); //print board board.printBoard(); // print player cards System.out.println("The player cards are the following:\n"); for (int i=0;i&lt;numPlayers;i++){ player[i].printPlayerCards(i); } // print burn cards board.printBurnCards(); //------------------------ // Begin hand comparison //------------------------ for (int i=0;i&lt;numPlayers;i++){ HandEval handToEval = new HandEval(); // populate with player cards for (int j=0;j&lt;player[i].holeCardsSize();j++){ handToEval.addCard(player[i].getCard(j),j); } //populate with board cards for (int j=player[i].holeCardsSize();j&lt;(player[i].holeCardsSize()+board.boardSize());j++){ handToEval.addCard(board.getBoardCard(j-player[i].holeCardsSize()),j); } System.out.println("Player " + (i+1) + " hand value: " + handToEval.evaluateHand()); } } protected static int getNumberOfPlayers() throws Exception{ int intPlayers = 0; String userInput = ""; // Get number of players from user. System.out.println("Enter number of players (1-9):"); BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); try { userInput = br.readLine(); } catch (IOException ioe) { System.out.println("Error: IO error trying to read input!"); System.exit(1); } // convert user input to an integer try { intPlayers = Integer.parseInt(userInput); } catch (NumberFormatException nfe) { System.out.println("Error: Input provided is not a valid Integer!"); System.exit(1); } if ((intPlayers&lt;1) || (intPlayers&gt;9)){ throw new Exception("Error: Number of players must be an integer between 1 and 9"); } return intPlayers; } } </code></pre> <p><a href="http://pastebin.com/rDGwn9r7" rel="nofollow noreferrer">Player.java</a> </p> <pre><code>public class Player { private Card[] holeCards = new Card[2]; //constructor public Player(){ } public Player(Card card1, Card card2){ holeCards[0] = card1; holeCards[1] = card2; } //methods protected void setCard(Card card, int cardNum){ holeCards[cardNum] = card; } protected Card getCard(int cardNum){ return holeCards[cardNum]; } protected int holeCardsSize(){ return holeCards.length; } protected void printPlayerCards(int playerNumber){ System.out.println("Player " + (playerNumber+1) + " hole cards:"); for (int i=0;i&lt;2;i++){ System.out.println(holeCards[i].printCard()); } System.out.println("\n"); } } </code></pre> <p><a href="http://pastebin.com/eA9L2vXv" rel="nofollow noreferrer">HandEval.java</a> </p> <pre><code>import java.util.Arrays; public class HandEval { private Card[] availableCards = new Card[7]; private final static short ONE = 1; private final static short TWO = 2; private final static short THREE = 3; private final static short FOUR = 4; // Constructor public HandEval(){ } //methods protected void addCard(Card card, int i){ availableCards[i] = card; } protected Card getCard(int i){ return availableCards[i]; } protected int numCards(){ return availableCards.length; } protected void sortByRank(){ Arrays.sort(availableCards, new rankComparator()); } protected void sortBySuit(){ Arrays.sort(availableCards, new suitComparator()); } protected void sortBySuitThenRank(){ Arrays.sort(availableCards, new suitComparator()); Arrays.sort(availableCards, new rankComparator()); } protected void sortByRankThenSuit(){ Arrays.sort(availableCards, new rankComparator()); Arrays.sort(availableCards, new suitComparator()); } protected String evaluateHand(){ String handResult = new String(); short[] rankCounter = new short[13]; short[] suitCounter = new short[4]; // initializations for (int i=0;i&lt;rankCounter.length;i++){ rankCounter[i] =0; } for (int i=4;i&lt;suitCounter.length;i++){ suitCounter[i] = 0; } // Loop through sorted cards and total ranks for(int i=0; i&lt;availableCards.length;i++){ rankCounter[ availableCards[i].getRank() ]++; suitCounter[ availableCards[i].getSuit() ]++; } //sort cards for evaluation this.sortByRankThenSuit(); // hands are already sorted by rank and suit for royal and straight flush checks. // check for royal flush handResult = evaluateRoyal(rankCounter, suitCounter); // check for straight flush if (handResult == null || handResult.length() == 0){ handResult = evaluateStraightFlush(rankCounter, suitCounter); } // check for four of a kind if (handResult == null || handResult.length() == 0){ handResult = evaluateFourOfAKind(rankCounter); } // check for full house if (handResult == null || handResult.length() == 0){ handResult = evaluateFullHouse(rankCounter); } // check for flush if (handResult == null || handResult.length() == 0){ handResult = evaluateFlush(rankCounter, suitCounter); } // check for straight if (handResult == null || handResult.length() == 0){ // re-sort by rank, up to this point we had sorted by rank and suit // but a straight is suit independent. this.sortByRank(); handResult = evaluateStraight(rankCounter); } // check for three of a kind if (handResult == null || handResult.length() == 0){ handResult = evaluateThreeOfAKind(rankCounter); } // check for two pair if (handResult == null || handResult.length() == 0){ handResult = evaluateTwoPair(rankCounter); } // check for one pair if (handResult == null || handResult.length() == 0){ handResult = evaluateOnePair(rankCounter); } // check for highCard if (handResult == null || handResult.length() == 0){ handResult = evaluateHighCard(rankCounter); } return handResult; } private String evaluateRoyal(short[] rankCounter, short[] suitCounter){ String result = ""; // Check for Royal Flush (10 - Ace of the same suit). // check if there are 5 of one suit, if not royal is impossible if ((rankCounter[9] &gt;= 1 &amp;&amp; /* 10 */ rankCounter[10] &gt;= 1 &amp;&amp; /* Jack */ rankCounter[11] &gt;= 1 &amp;&amp; /* Queen */ rankCounter[12] &gt;= 1 &amp;&amp; /* King */ rankCounter[0] &gt;= 1) /* Ace */ &amp;&amp; (suitCounter[0] &gt; 4 || suitCounter[1] &gt; 4 || suitCounter[2] &gt; 4 || suitCounter[3] &gt; 4)){ // min. requirements for a royal flush have been met, // now loop through records for an ace and check subsequent cards. // Loop through the aces first since they are the first card to // appear in the sorted array of 7 cards. royalSearch: for (int i=0;i&lt;3;i++){ // Check if first card is the ace. // Ace must be in position 0, 1 or 2 if (availableCards[i].getRank() == 0){ // because the ace could be the first card in the array // but the remaining 4 cards could start at position 1, // 2 or 3 loop through checking each possibility. for (int j=1;j&lt;4-i;j++){ if ((availableCards[i+j].getRank() == 9 &amp;&amp; availableCards[i+j+1].getRank() == 10 &amp;&amp; availableCards[i+j+2].getRank() == 11 &amp;&amp; availableCards[i+j+3].getRank() == 12) &amp;&amp; (availableCards[i].getSuit() == availableCards[i+j].getSuit() &amp;&amp; availableCards[i].getSuit() == availableCards[i+j+1].getSuit() &amp;&amp; availableCards[i].getSuit() == availableCards[i+j+2].getSuit() &amp;&amp; availableCards[i].getSuit() == availableCards[i+j+3].getSuit())){ // Found royal flush, break and return. result = "Royal Flush!! Suit: " + Card.suitAsString(availableCards[i].getSuit()); break royalSearch; } } } } } return result; } // Straight flush is 5 consecutive cards of the same suit. private String evaluateStraightFlush(short[] rankCounter, short[] suitCounter){ String result = ""; if (suitCounter[0] &gt; 4 || suitCounter[1] &gt; 4 || suitCounter[2] &gt; 4 || suitCounter[3] &gt; 4){ // min. requirements for a straight flush have been met. // Loop through available cards looking for 5 consecutive cards of the same suit, // start in reverse to get the highest value straight flush for (int i=availableCards.length-1;i&gt;3;i--){ if ((availableCards[i].getRank()-ONE == availableCards[i-ONE].getRank() &amp;&amp; availableCards[i].getRank()-TWO == availableCards[i-TWO].getRank() &amp;&amp; availableCards[i].getRank()-THREE == availableCards[i-THREE].getRank() &amp;&amp; availableCards[i].getRank()-FOUR == availableCards[i-FOUR].getRank()) &amp;&amp; (availableCards[i].getSuit() == availableCards[i-ONE].getSuit() &amp;&amp; availableCards[i].getSuit() == availableCards[i-TWO].getSuit() &amp;&amp; availableCards[i].getSuit() == availableCards[i-THREE].getSuit() &amp;&amp; availableCards[i].getSuit() == availableCards[i-FOUR].getSuit())){ // Found royal flush, break and return. result = "Straight Flush!! " + Card.rankAsString(availableCards[i].getRank()) + " high of " + Card.suitAsString(availableCards[i].getSuit()); break; } } } return result; } // Four of a kind is 4 cards with the same rank: 2-2-2-2, 3-3-3-3, etc... private String evaluateFourOfAKind(short[] rankCounter){ String result = ""; for (int i=0;i&lt;rankCounter.length;i++){ if (rankCounter[i] == FOUR){ result = "Four of a Kind, " + Card.rankAsString(i) +"'s"; break; } } return result; } // Full house is having 3 of a kind of one rank, and two of a kind of // a second rank. EX: J-J-J-3-3 private String evaluateFullHouse(short[] rankCounter){ String result = ""; short threeOfKindRank = -1; short twoOfKindRank = -1; for (int i=rankCounter.length;i&gt;0;i--){ if ((threeOfKindRank &lt; (short)0) || (twoOfKindRank &lt; (short)0)){ if ((rankCounter[i-ONE]) &gt; 2){ threeOfKindRank = (short) (i-ONE); } else if ((rankCounter[i-ONE]) &gt; 1){ twoOfKindRank = (short)(i-ONE); } } else { break; } } if ((threeOfKindRank &gt;= (short)0) &amp;&amp; (twoOfKindRank &gt;= (short)0)){ result = "Full House: " + Card.rankAsString(threeOfKindRank) + "'s full of " + Card.rankAsString(twoOfKindRank) + "'s"; } return result; } // Flush is 5 cards of the same suit. private String evaluateFlush(short[] rankCounter, short[] suitCounter){ String result = ""; // verify at least 1 suit has 5 cards or more. if (suitCounter[0] &gt; 4 || suitCounter[1] &gt; 4 || suitCounter[2] &gt; 4 || suitCounter[3] &gt; 4){ for (int i=availableCards.length-1;i&gt;3;i--){ if (availableCards[i].getSuit() == availableCards[i-ONE].getSuit() &amp;&amp; availableCards[i].getSuit() == availableCards[i-TWO].getSuit() &amp;&amp; availableCards[i].getSuit() == availableCards[i-THREE].getSuit() &amp;&amp; availableCards[i].getSuit() == availableCards[i-FOUR].getSuit()){ // Found royal flush, break and return. result = "Flush!! " + Card.rankAsString(availableCards[i].getRank()) + " high of " + Card.suitAsString(availableCards[i].getSuit()); break; } } } return result; } // Straight is 5 consecutive cards, regardless of suit. private String evaluateStraight(short[] rankCounter){ String result = ""; // loop through rank array to check for 5 consecutive // index with a value greater than zero for (int i=rankCounter.length;i&gt;4;i--){ if ((rankCounter[i-1] &gt; 0) &amp;&amp; (rankCounter[i-2] &gt; 0) &amp;&amp; (rankCounter[i-3] &gt; 0) &amp;&amp; (rankCounter[i-4] &gt; 0) &amp;&amp; (rankCounter[i-5] &gt; 0)){ result = "Straight " + Card.rankAsString(i-1) + " high"; break; } } return result; } // Three of a kind is 3 cards of the same rank. private String evaluateThreeOfAKind(short[] rankCounter){ String result = ""; // loop through rank array to check for 5 consecutive // index with a value greater than zero for (int i=rankCounter.length;i&gt;0;i--){ if (rankCounter[i-1] &gt; 2){ result = "Three of a Kind " + Card.rankAsString(i-1) + "'s"; break; } } return result; } // Two pair is having 2 cards of the same rank, and two // different cards of the same rank. EX: 3-3-7-7-A private String evaluateTwoPair(short[] rankCounter){ String result = ""; short firstPairRank = -1; short secondPairRank = -1; for (int i=rankCounter.length;i&gt;0;i--){ if ((firstPairRank &lt; (short)0) || (secondPairRank &lt; (short)0)){ if (((rankCounter[i-ONE]) &gt; 1) &amp;&amp; (firstPairRank &lt; (short)0)){ firstPairRank = (short) (i-ONE); } else if ((rankCounter[i-ONE]) &gt; 1){ secondPairRank = (short)(i-ONE); } } else { // two pair found, break loop. break; } } // populate output if ((firstPairRank &gt;= (short)0) &amp;&amp; (secondPairRank &gt;= (short)0)){ if (secondPairRank == (short)0){ // Aces serve as top rank but are at the bottom of the rank array // swap places so aces show first as highest pair result = "Two Pair: " + Card.rankAsString(secondPairRank) + "'s and " + Card.rankAsString(firstPairRank) + "'s"; } else { result = "Two Pair: " + Card.rankAsString(firstPairRank) + "'s and " + Card.rankAsString(secondPairRank) + "'s"; } } return result; } // One is is two cards of the same rank. private String evaluateOnePair(short[] rankCounter){ String result = ""; for (int i=rankCounter.length;i&gt;0;i--){ if((rankCounter[i-ONE]) &gt; 1){ result = "One Pair: " + Card.rankAsString(i-ONE) + "'s"; break; } } return result; } // high card is the highest card out of the 7 possible cards to be used. private String evaluateHighCard(short[] rankCounter){ String result = ""; for (int i=rankCounter.length;i&gt;0;i--){ if((rankCounter[i-ONE]) &gt; 0){ result = "High Card: " + Card.rankAsString(i-ONE); break; } } return result; } } </code></pre> <p><a href="http://pastebin.com/fC7wwMcd" rel="nofollow noreferrer">Deck.java</a> </p> <pre><code>import java.util.Random; public class Deck{ private Card[] cards = new Card[52]; //Constructor public Deck(){ int i = 0; for (short j=0; j&lt;4; j++){ for (short k=0; k&lt;13;k++){ cards[i++] = new Card(k, j); } } } // Print entire deck in order protected void printDeck(){ for(int i=0; i&lt;cards.length;i++){ System.out.println(i+1 + ": " + cards[i].printCard()); } System.out.println("\n"); } // Find card in deck in a linear fashion // Use this method if deck is shuffled/random protected int findCard(Card card){ for (int i=0;i&lt;52;i++){ if (Card.sameCard(cards[i], card)){ return i; } } return -1; } //return specified card from deck protected Card getCard(int cardNum){ return cards[cardNum]; } protected void shuffle(){ int length = cards.length; Random random = new Random(); //random.nextInt(); for (int i=0;i&lt;length;i++){ int change = i + random.nextInt(length-i); swapCards(i, change); } } protected void cutDeck(){ Deck tempDeck = new Deck(); Random random = new Random(); int cutNum = random.nextInt(52); for (int i=0;i&lt;cutNum;i++){ tempDeck.cards[i] = this.cards[52-cutNum+i]; } for (int j=0;j&lt;52-cutNum;j++){ tempDeck.cards[j+cutNum] = this.cards[j]; } this.cards = tempDeck.cards; } // Swap cards in array to 'shuffle' the deck. private void swapCards(int i, int change){ Card temp = cards[i]; cards[i] = cards[change]; cards[change] = temp; } } </code></pre> <p><a href="http://pastebin.com/a8P7jweg" rel="nofollow noreferrer">Card.java</a> </p> <pre><code>import java.util.*; public class Card{ private short rank, suit; private static String[] ranks = {"Ace", "2", "3", "4", "5", "6", "7", "8", "9", "10", "Jack", "Queen", "King"}; private static String[] suits = {"Diamonds", "Clubs", "Hearts", "Spades"}; //Constructor public Card(short rank, short suit){ this.rank = rank; this.suit = suit; } // Getter and Setters public short getSuit(){ return suit; } public short getRank(){ return rank; } protected void setSuit(short suit){ this.suit = suit; } protected void setRank(short rank){ this.rank = rank; } // methods public static String rankAsString(int __rank){ return ranks[__rank]; } public static String suitAsString(int __suit){ return suits[__suit]; } public @Override String toString(){ return rank + " of " + suit; } // Print card to string protected String printCard(){ return ranks[rank] + " of " + suits[suit]; } // Determine if two cards are the same (Ace of Diamonds == Ace of Diamonds) public static boolean sameCard(Card card1, Card card2){ return (card1.rank == card2.rank &amp;&amp; card1.suit == card2.suit); } } class rankComparator implements Comparator&lt;Object&gt;{ public int compare(Object card1, Object card2) throws ClassCastException{ // verify two Card objects are passed in if (!((card1 instanceof Card) &amp;&amp; (card2 instanceof Card))){ throw new ClassCastException("A Card object was expeected. Parameter 1 class: " + card1.getClass() + " Parameter 2 class: " + card2.getClass()); } short rank1 = ((Card)card1).getRank(); short rank2 = ((Card)card2).getRank(); return rank1 - rank2; } } class suitComparator implements Comparator&lt;Object&gt;{ public int compare(Object card1, Object card2) throws ClassCastException{ // verify two Card objects are passed in if (!((card1 instanceof Card) &amp;&amp; (card2 instanceof Card))){ throw new ClassCastException("A Card object was expeected. Parameter 1 class: " + card1.getClass() + " Parameter 2 class: " + card2.getClass()); } short suit1 = ((Card)card1).getSuit(); short suit2 = ((Card)card2).getSuit(); return suit1 - suit2; } } </code></pre> <p><a href="http://pastebin.com/Rh7wH8Ea" rel="nofollow noreferrer">Board.java</a> </p> <pre><code>public class Board { private Card[] board = new Card[5]; private Card[] burnCards = new Card[3]; //constructor public Board(){ } //methods protected void setBoardCard(Card card, int cardNum){ this.board[cardNum] = card; } protected Card getBoardCard(int cardNum){ return this.board[cardNum]; } protected void setBurnCard(Card card, int cardNum){ this.burnCards[cardNum] = card; } protected Card getBurnCard(int cardNum){ return this.burnCards[cardNum]; } protected int boardSize(){ return board.length; } protected void printBoard(){ System.out.println("The board contains the following cards:"); for(int i =0; i&lt;board.length;i++){ System.out.println(i+1 + ": " + getBoardCard(i).printCard()); } System.out.println("\n"); } protected void printBurnCards(){ System.out.println("The burn cards are:"); for(int i =0; i&lt;burnCards.length;i++){ System.out.println(i+1 + ": " + getBurnCard(i).printCard()); } System.out.println("\n"); } } </code></pre>

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<p>I wrote a simple PHP script which allows the user to upload a file to the server. It works, but I'm not very sure about security. Could you give me some hints about security mistakes?</p> <p>In a nutshell: The user uploads a file from form.html, then a file is saved in uploads/ directory on the server, and a direct link to it is recorded in a database. Then that link is presented to the user, so he/she is able to download the file. The execution of that file is forbidden using .htaccess.</p> <p><strong>form.html</strong></p> <pre><code>&lt;div id="quickFileSubmit" style="margin-left: 20px; display: none"&gt; &lt;table&gt; &lt;tr&gt; &lt;td&gt; &lt;form enctype="multipart/form-data" class="smallForm" action="action.php?act=quickFileSubmit" method="post" style="margin-top: 5px;"&gt; &lt;label style="font-size: 12px;"&gt;File:&lt;/label&gt; &lt;input type="file" name="uploadfile" readonly="true" size="30"/&gt; &lt;input type="submit" value="Submit" /&gt; &lt;/form&gt; &lt;/td&gt; &lt;td style="width: 100%;"&gt;&lt;/td&gt; &lt;/tr&gt; &lt;/table&gt; &lt;/div&gt; </code></pre> <p><strong>action.php</strong></p> <pre><code>//some actions else if ($_REQUEST["act"] == "quickFileSubmit") { $basename = getUploadBasename(); uploadFile(); header("location:index.php"); } function uploadFile() { if (strlen($_FILES['uploadfile']["name"]) &gt; 0) { $target_path = "uploads/"; $basename = basename( $_FILES['uploadfile']['name']); $target_path = $target_path . $basename; if (encode($basename) == $basename) { if(move_uploaded_file($_FILES['uploadfile']['tmp_name'], $target_path)) { // here goes saving of file info return $basename; } else{ // upload failed. echo "File upload failed."; return null; } } else { echo "Illegal characters in file name."; return null; } } } </code></pre> <p>Also, I have put .htaccess in the uploads dir:</p> <p><strong>.htaccess</strong></p> <pre><code>SetHandler default-handler Options -Indexes </code></pre>

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<p>Just as the question states and to be sure, am I missing anything on this? Something important/obvious that I overlooked? As is, I can save any functor, function pointer and member function pointer using this delegate class (copy ctor and assignment operator left out for brevity, as were the versions with parameters).</p> <pre><code>template&lt;class Type&gt; void Deleter(void* object){ Type* obj_ptr = static_cast&lt;Type*&gt;(object); delete obj_ptr; } template&lt;class Functor&gt; struct DelegateHelper{ typedef typename Functor::result_type result_type; DelegateHelper(Functor func) : func_(func) {} result_type operator()(){ return func_(); } Functor func_; }; template&lt;class Obj, class R&gt; struct DelegateHelper&lt;R (Obj::*)()&gt;{ typedef R (Obj::*FuncPtr)(); DelegateHelper(Obj* obj_ptr, FuncPtr func) : object_(obj_ptr) , func_(func) {} R operator()(){ return (object_-&gt;*func_)(); } Obj* object_; FuncPtr func_; }; template&lt;class R&gt; struct DelegateHelper&lt;R (*)()&gt;{ typedef R (*FuncPtr)(); DelegateHelper(FuncPtr func) : func_(func) {} R operator()(){ return (*func_)(); } FuncPtr func_; }; template&lt;class Sig&gt; struct Delegate; template&lt;class R&gt; struct Delegate&lt;R ()&gt;{ typedef R (*SinkPtr)(void*); Delegate() : object_(0) , func_(0) , deleter_(0) {} template&lt;class F&gt; Delegate(F func) : object_(new DelegateHelper&lt;F&gt;(func)) , func_(&amp;Sink&lt;DelegateHelper&lt;F&gt; &gt;) , deleter_(&amp;Deleter&lt;DelegateHelper&lt;F&gt; &gt;) {} template&lt;class C, class F&gt; Delegate(C* obj, F func) : object_(new DelegateHelper&lt;F&gt;(obj, func)) , func_(&amp;Sink&lt;DelegateHelper&lt;F&gt; &gt;) , deleter_(&amp;Deleter&lt;DelegateHelper&lt;F&gt; &gt;) {} ~Delegate(){ if(deleter_) (*deleter_)(object_); } R operator()(){ return (*func_)(object_); } template&lt;class Type&gt; static R Sink(void* obj_ptr){ Type* object = (Type*)obj_ptr; return (*object)(); } typedef void (*DeleteFunc)(void*); void* object_; SinkPtr func_; DeleteFunc deleter_; }; </code></pre> <p>For the delegate in effect, <a href="http://ideone.com/PSi9j" rel="nofollow">see here on Ideone</a>.</p>

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<p>Inside of a folder named <code>txt</code> I have 138 text files (totaling 349MB) full of email addresses. I have no idea (yet) how many addresses there are. They are separated from one another by line breaks. I created the following script to read all of these files into an array, dismiss the duplicates, then sort alphabetically and save in groups of 10K per csv file. It works correctly, but it has also been running for over 8 hours (dual core i3 w/ 4 gigabizzles of ram, sata 7200 hdd) which seems excessive to me. <code>Top</code> also tells me that my program's CPU usage is 100% and it's been like that the whole while it's been running. Give my script a looksie and advise me on where I've gone so terribly wrong.</p> <pre><code>function writeFile($fileName, $fileData) { $writeFileOpen = fopen('csv/' . $fileName, 'w'); fwrite($writeFileOpen, $fileData) or die('Unable to write file: ' . $fileName); fclose($writeFileOpen); } function openFiles() { $addressList = array(); $preventRepeat = array(); if ($handle = opendir('txt')) { while (false !== ($file = readdir($handle))) { if ($file != '.' &amp;&amp; $file != '..') { $newList = explode("\n", trim(file_get_contents('txt/' . $file))); foreach ($newList as $key =&gt; $val) { $val = str_replace(array(',', '"'), '', $val); if (in_array($val, $preventRepeat) || !strpos($val, '@') || !$val) { unset($newList[$key]); } $preventRepeat[] = $val; } if (empty($addressList)) { $addressList = $newList; } else { $addressList = array_merge($addressList, $newList); } unset($newList); } } closedir($handle); } else { echo 'Unable to Read Directory'; } $lineNum = 1; $fileNum = 1; $fileData = '"Email Address"' . "\n"; sort($addressList); $lastKey = count($addressList) - 1; foreach ($addressList as $key =&gt; $val) { if ($lineNum &gt; 10000) { writeFile('emailList-' . $fileNum . '.csv', trim($fileData)); $lineNum = 1; $fileNum++; $fileData = '"Email Address"' . "\n"; } elseif ($key == $lastKey) { writeFile('emailList-' . $fileNum . '.csv', trim($fileData)); echo 'Complete'; } $fileData .= '"' . trim($val) . '"' . "\n"; $lineNum++; } } openFiles(); </code></pre> <p>PS. I wrote this script in haste to accomplish a task. I can understand if you wouldn't consider this script <em>distribution</em> worthy.</p> <p>EDIT: So I arrived at work today to find my script at some point exceeded 536MB of memory and quit on fatal error. I had already increased my ini file's <code>memory_limit</code> parameter from 128MB to 512MB. This doesn't necessarily reflect an issue with the script itself. I just wanted to share my frustration with the task.</p>

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<p>I was trying to do a very common interview problem "Finding the max repeated word in a string " and could not find much resources in net for c/c++ implementation. So I coded it myself here. I have tried to do most of the coding from scratch for better understanding. Could you review my code and provide comments on my algorithm. Some people have suggested using hashtables for storing the count, but am not using hashtables here.</p> <pre><code>#include&lt;stdafx.h&gt; #include&lt;stdlib.h&gt; #include&lt;stdio.h&gt; #include&lt;string&gt; #include&lt;iostream&gt; using namespace std; string word[10]; //splitting string into words int parsestr(string str) { int index = 0; int i = 0; int maxlength = str.length(); int wordcnt = 0; while(i &lt; maxlength) { if(str[i] != ' ') { word[index] = word[index] + str[i]; } else { index++; //new word wordcnt = index; } i++; } return wordcnt; } //find the max word count out of the array and return the word corresponding to that index. string maxrepeatedWord(int wordcntArr[],int count) { int max = 0; int index = 0; for(int i = 0; i &lt;= count; i++) { if(wordcntArr[i] &gt; max) { max = wordcntArr[i]; index = i; } } return word[index]; } void countwords(int count) { int wordcnt = 0; int wordcntArr[10]; string maxrepeatedword; for(int i = 0; i &lt;= count; i++) { for(int j = 0; j &lt;= count; j++) { if(word[i] == word[j]) { wordcnt++; //word[j] = ""; } else {} } cout &lt;&lt; " word " &lt;&lt; word[i] &lt;&lt; " occurs " &lt;&lt; wordcnt &lt;&lt; " times " &lt;&lt; endl; wordcntArr[i] = wordcnt; wordcnt = 0; } maxrepeatedword = maxrepeatedWord(wordcntArr,count); cout &lt;&lt; " Max Repeated Word is " &lt;&lt; maxrepeatedword; } int main() { string str = "I am am am good good"; int wordcount = 0; wordcount = parsestr(str); countwords(wordcount); } </code></pre>

1394

<p>Given the following problem (SICP Exercise 1.3):</p> <blockquote> <p>Define a procedure that takes three numbers as arguments and returns the sum of squares of the two largest numbers.</p> </blockquote> <p>I wrote the following (somewhat clumsy) solution in Scheme. How can I make it better?</p> <pre><code>(define (greatest-two a b c) (cond ((&gt; a b) (cond ((&gt; b c) (list a b)) (else (list a c)))) ((&gt; a c) (cond ((&gt; c b) (list a c)) (else (list a b)))) (else (list b c)))) (define (square x) (* x x)) (define (sum-of-squares a b) (+ (square a) (square b))) (define (f a b c) (apply sum-of-squares (greatest-two a b c))) </code></pre>

1395

<p>Given the following task:</p> <blockquote> <p>Use Newton's method to compute the square root of a number. Newton's method involves successive approximation. You start with a guess, and then continue averaging successive guesses until you reach a satisfactory level of precision.</p> </blockquote> <p>I wrote the following (rough) solution in Scheme. Can you help me make it better?</p> <pre><code>(define (abs x) ((if (&lt; x 0) - +) x)) (define (almost-equal x y delta) (&gt; delta (abs (- x y)))) (define (sqrt-prime x last-x) (let ((next-x (/ (+ x last-x) 2))) (if (almost-equal next-x x 0.000001) x (sqrt-prime next-x x)))) (define (sqrt x) (sqrt-prime x 1)) </code></pre>

1396

<p>I've implemented a <code>let-with</code> macro that takes an association list, keyed by symbols, that enables code to bind their corresponding values to local variables.</p> <p>It's designed to have a similar effect to JavaScript's <code>with</code>, but without <a href="http://yuiblog.com/blog/2006/04/11/with-statement-considered-harmful/" rel="nofollow"><code>with</code>'s attendant problems</a> (by making you explicitly list the variables to bind).</p> <pre class="lang-lisp prettyprint-override"><code>(define-syntax let-with (syntax-rules () ((let-with alist (key ...) expr ...) (let ((key (cond ((assq 'key alist) =&gt; cdr))) ...) expr ...)))) </code></pre> <p>I'd love to hear of any improvements to <code>let-with</code>'s interface and/or implementation.</p> <p>Example usage:</p> <pre class="lang-lisp prettyprint-override"><code>(define alist '((first . "Jane") (last . "Doe"))) (let-with alist (first last) (string-append first " " last)) ; "Jane Doe" </code></pre> <p>Keys that don't exist in the incoming alist receive an undefined value; they do not fail to get bound, unlike JavaScript's <code>with</code>.</p>

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<p>Newton's method for finding cube roots states that for any given \$x\$ and a guess \$y\$, a better approximation is \$\dfrac{(\dfrac{x}{y^2} + 2y)}{3}\$.</p> <p>What do you think of this code for finding a cube root in Scheme?</p> <pre><code>(define (improveguess y x) ; y is a guess for cuberoot(x) (/ (+ (/ x (expt y 2)) (* 2 y)) 3)) (define (cube x) (* x x x)) (define (goodenough? guess x) (&lt; (/ (abs (- (cube guess) x)) guess) 0.0001)) (define (cuberoot x) (cuberoot-iter 1.0 x)) (define (cuberoot-iter guess x) (if (goodenough? guess x) guess (cuberoot-iter (improveguess guess x) x))) </code></pre>

1401

<p>Here's my function for getting the length of a file, in characters:</p> <pre><code>unsigned int GetFileLength(std::string FileName) { std::ifstream InFile(FileName.c_str()); unsigned int FileLength = 0; while (InFile.get() != EOF) FileLength++; InFile.close(); return FileLength; } </code></pre> <p>How can this be improved?</p>

1405

<p>I wrote the following JPA method that queries a database to return a distinct list of a String field (called mtfcc) of a Location object. I then took the list of strings to query for the associated name for that MTFCC.</p> <p>Could I just modify the first query to get the results, without having to use the for loop to get the associated name field?</p> <pre><code>@Override public Map&lt;String, String&gt; getAvailableBorderTypes() { // create empty map to store results in. If we don't find results, an empty hashmap will be returned Map&lt;String, String&gt; results = new HashMap&lt;String, String&gt;(); EntityManager em = entityManagerFactory.createEntityManager(); // get the distinct mtfcc's String jpaQuery = "SELECT DISTINCT location.mtfcc FROM Location location"; // get the distinct mtfcc codes List&lt;String&gt; mtfccList = (List&lt;String&gt;) em.createQuery(jpaQuery).getResultList(); // cycle through the mtfcc list and get the name to associate with it for (String mtfcc: mtfccList) { String nameQuery = "SELECT DISTINCT location.name FROM Location location WHERE location.mtfcc = ?1"; String name = (String) em.createQuery(nameQuery).setParameter(1, mtfcc).getSingleResult(); results.put(mtfcc, name); } return results; } </code></pre>

1409

<p>In Python, <code>itertools.combinations</code> yields combinations of elements in a sequence sorted by lexicographical order. In the course of solving certain math problems, I found it useful to write a function, <code>combinations_by_subset</code>, that yields these combinations sorted by subset order (for lack of a better name).</p> <p>For example, to list all 3-length combinations of the string 'abcde':</p> <pre><code>&gt;&gt;&gt; [''.join(c) for c in itertools.combinations('abcde', 3)] ['abc', 'abd', 'abe', 'acd', 'ace', 'ade', 'bcd', 'bce', 'bde', 'cde'] &gt;&gt;&gt; [''.join(c) for c in combinations_by_subset('abcde', 3)] ['abc', 'abd', 'acd', 'bcd', 'abe', 'ace', 'bce', 'ade', 'bde', 'cde'] </code></pre> <p>Formally, for a sequence of length \$n\$, we have \$\binom{n}{r}\$ combinations of length \$r\$, where \$\binom{n}{r} = \frac{n!}{r! (n - r)!}\$</p> <p>The function <code>combinations_by_subset</code> yields combinations in such an order that the first \$\binom{k}{r}\$ of them are the r-length combinations of the first k elements of the sequence.</p> <p>In our example above, the first \$\binom{3}{3} = 1\$ combination is the 3-length combination of 'abc' (which is just 'abc'); the first \$\binom{4}{3} = 4\$ combinations are the 3-length combinations of 'abcd' (which are 'abc', 'abd', 'acd', 'bcd'); etc.</p> <p>My first implementation is a simple generator function:</p> <pre><code>def combinations_by_subset(seq, r): if r: for i in xrange(r - 1, len(seq)): for cl in (list(c) for c in combinations_by_subset(seq[:i], r - 1)): cl.append(seq[i]) yield tuple(cl) else: yield tuple() </code></pre> <p>For fun, I decided to write a second implementation as a generator expression and came up with the following:</p> <pre><code>def combinations_by_subset(seq, r): return (tuple(itertools.chain(c, (seq[i], ))) for i in xrange(r - 1, len(seq)) for c in combinations_by_subset(seq[:i], r - 1)) if r else (() for i in xrange(1)) </code></pre> <p>My questions are:</p> <ol> <li>Which function definition is preferable? (I prefer the generator function over the generator expression because of legibility.)</li> <li>Are there any improvements one could make to the above algorithm/implementation?</li> <li>Can you suggest a better name for this function?</li> </ol>

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<p>I just found out about the existence of this forum and it's exactly what I needed. I just asked <a href="https://stackoverflow.com/questions/5386795/how-to-safely-save-data-to-an-existing-file-with-c">this</a> question on Stack Overflow and after reading the answers I came up with a code (not the one I posted there but the one I'm posting here).</p> <p>First, this is my messed up code:</p> <pre><code>string tempFile = Path.GetTempFileName(); using (Stream tempFileStream = File.Open(tempFile, FileMode.Truncate)) { SafeXmlSerializer xmlFormatter = new SafeXmlSerializer(typeof(Project)); xmlFormatter.Serialize(tempFileStream, Project); } if (File.Exists(fileName)) File.Delete(fileName); File.Move(tempFile, fileName); if (File.Exists(tempFile)) File.Delete(tempFile); </code></pre> <p>When saving to an existing file that is in my Dropbox, it will, sometimes, delete the original file and fail to move the temporary file to the original location in <code>File.Move(tempFile, fileName);</code>. So here is my new code that I think it should never, unless the OS became self-conscious and evil, delete the original file without saving the new one. The worst it can happens is that the original will be renamed and will stay like that and I will have to let the user know (see the <code>MessageBox</code> at the bottom):</p> <pre><code>private string GetTempFileName(string dir) { string name = null; int attempts = 0; do { name = "temp_" + Player.Math.RandomDigits(10) + ".hsp"; attempts++; if (attempts &gt; 10) throw new Exception("Could not create temporary file."); } while (File.Exists(Path.Combine(dir, name))); return name; } private void TryToDelete(string path) { try { File.Delete(path); } catch { } } private void SaveProject(string fileName) { bool originalRenamed = false; string tempNewFile = null; string oldFileTempName = null; Exception exception = null; try { tempNewFile = GetTempFileName(Path.GetDirectoryName(fileName)); using (Stream tempNewFileStream = File.Open(tempNewFile, FileMode.CreateNew)) { SafeXmlSerializer xmlFormatter = new SafeXmlSerializer(typeof(Project)); xmlFormatter.Serialize(tempNewFileStream, Project); } if (File.Exists(fileName)) { oldFileTempName = GetTempFileName(Path.GetDirectoryName(fileName)); File.Move(fileName, oldFileTempName); originalRenamed = true; } File.Move(tempNewFile, fileName); originalRenamed = false; CurrentProjectPath = fileName; } catch (Exception ex) { exception = ex; } finally { if (tempNewFile != null) TryToDelete(tempNewFile); if (originalRenamed) { try { File.Move(oldFileTempName, fileName); originalRenamed = false; } catch { } } if (exception != null) MessageBox.Show(exception.Message); if (originalRenamed) { MessageBox.Show("'" + fileName + "'" + " have been corrupted or deleted in this operation.\n" + "A backup copy have been created at '" + oldFileTempName + "'"); } else if (oldFileTempName != null) TryToDelete(oldFileTempName); } } </code></pre> <p><code>Player.Math.RandomDigits</code> is just a function that returns a string with random digits. Do you think my code is safe as I think it is or am I missing something? It's hard for me to test every possible exception.</p>

1420

<p>The following code has one of the most confusing lines I've ever wrote. I can imagine ten other way to write it but I do not know which else could be any better.</p> <p>Note:</p> <p><code>Db()</code> is very similar to <code>PDO()</code>, it just extends it adding few features I'm not using here.</p> <p><code>Post::addExtra()</code> add abstract datas elaborating database data.</p> <p>For example he created a <code>$data[13] = $data['from db1'] .' with '. $data['from db2']</code>. These because they are going to be passed to the template.</p> <pre><code>$db = new Db(); $s = new Session(); # Default statement and parameters $stmt = "SELECT p.PostPID, p.PostUID, p.PostText, p.PostTime, u.UserUID, u.UserName, u.UserImage, u.UserRep, ( SELECT COUNT(*) FROM Flags as f JOIN Posts as p1 ON p1.PostPID = f.FlagPID WHERE p1.PostPID = p.PostPID ) as PostFlags FROM Posts AS p JOIN Users AS u ON p.PostUID = u.UserUID ORDER BY PostTime DESC LIMIT 0, 30"; $par = array(); # We change the statement if the tab is selected if ($tab = get('tab')) { switch ($tab) { case 'admin': $stmt = "SELECT p.PostPID, p.PostUID, p.PostText, p.PostTime, u.UserUID, u.UserName, u.UserImage, u.UserRep, ( SELECT COUNT(*) FROM Flags as f JOIN Posts as p1 ON p1.PostPID = f.FlagPID WHERE p1.PostPID = p.PostPID ) as PostFlags FROM Posts AS p JOIN Users AS u ON p.PostUID = u.UserUID WHERE p.PostUID = 1 ORDER BY PostTime DESC LIMIT 0, 30"; break; case 'trusted': if ($s-&gt;isLogged()) { $stmt = "SELECT p.PostPID, p.PostUID, p.PostText, p.PostTime, u.UserUID, u.UserName, u.UserImage, u.UserRep, ( SELECT COUNT(*) FROM Flags as f JOIN Posts as p1 ON p1.PostPID = f.FlagPID WHERE p1.PostPID = p.PostPID ) as PostFlags FROM Posts AS p JOIN Users AS u ON p.PostUID = u.UserUID WHERE p.PostUID IN ( SELECT TrustedUID FROM Trust WHERE TrusterUID = :uid ) ORDER BY PostTime DESC LIMIT 0, 30"; $par = array('uid' =&gt; $s-&gt;getUID()); } else { $stmt = ''; } break; case 'favorite': if ($s-&gt;isLogged()) { $stmt = "SELECT p.PostPID, p.PostUID, p.PostText, p.PostTime, u.UserUID, u.UserName, u.UserImage, u.UserRep, ( SELECT COUNT(*) FROM Flags as f JOIN Posts as p1 ON p1.PostPID = f.FlagPID WHERE p1.PostPID = p.PostPID ) as PostFlags FROM Posts AS p JOIN Users AS u ON p.PostUID = u.UserUID WHERE p.PostPID IN ( SELECT FavoritePID FROM Favorites WHERE FavoriteUID = :uid ) ORDER BY PostTime DESC LIMIT 0, 30"; $par = array('uid' =&gt; $s-&gt;getUID()); } else { $stmt = ''; } break; case 'top': $weekAgo = time() - week; $monthAgo = time() - month; $stmt = "SELECT p.PostPID, p.PostUID, p.PostText, p.PostTime, u.UserUID, u.UserName, u.UserImage, u.UserRep, ( SELECT COUNT(*) FROM Flags as f JOIN Posts as p1 ON p1.PostPID = f.FlagPID WHERE p1.PostPID = p.PostPID ) as PostFlags FROM Posts AS p JOIN Users AS u ON p.PostUID = u.UserUID WHERE p.PostTime &gt; $monthAgo LIMIT 0, 3 UNION SELECT p.PostPID, p.PostUID, p.PostText, p.PostTime, u.UserUID, u.UserName, u.UserImage, u.UserRep, ( SELECT COUNT(*) FROM Flags as f JOIN Posts as p1 ON p1.PostPID = f.FlagPID WHERE p1.PostPID = p.PostPID ) as PostFlags FROM Posts AS p JOIN Users AS u ON p.PostUID = u.UserUID WHERE p.PostTime &gt; $weekAgo ORDER BY PostFlags DESC LIMIT 0, 30"; break; case 'recent': default: break; } } # Loading posts try { $sql = $db-&gt;prepare($stmt); $sql-&gt;execute($par); $posts['Data'] = $sql-&gt;fetchAll(); } catch (PDOException $e) { throw new MyEx($e-&gt;getMessage()); } if (count($posts['Data']) &gt; 0) { foreach ($posts['Data'] as &amp;$post) { $post = Post::addExtra($post); } } </code></pre>

1426

<p>I have the following left join LINQ query that is returning the results that I expect, but it does not "feel" right. I need <strong>ALL</strong> records from the <code>UserProfile</code> table.</p> <p>Then the <code>LastWinnerDate</code> is a single record from the winner table (possible multiple records) indicating the <code>DateTime</code> the last record was entered in that table for the user.</p> <ul> <li><code>WinnerCount</code> is the number of records for the user in the <code>winner</code> table (possible multiple records).</li> <li><code>Video1</code> is basically a <code>bool</code> indicating there is, or is not a record for the user in the <code>winner</code> table matching on a third table <code>Objective</code> (should be 1 or 0 rows).</li> <li><code>Quiz1</code> is same as <code>Video1</code> matching another record from <code>Objective</code> Table (should be 1 or 0 rows).</li> <li><code>Video</code> and <code>Quiz</code> is repeated 12 times because they're used for a report, which is to be displayed to a user listing all user records and indicate if they have met the objectives.</li> </ul> <p></p> <pre><code>var objectiveIds = new List&lt;int&gt;(); objectiveIds.AddRange(GetObjectiveIds(objectiveName, false)); var q = from up in MetaData.UserProfile select new RankingDTO { UserId = up.UserID, FirstName = up.FirstName, LastName = up.LastName, LastWinnerDate = ( from winner in MetaData.Winner where objectiveIds.Contains(winner.ObjectiveID) where winner.Active where winner.UserID == up.UserID orderby winner.CreatedOn descending select winner.CreatedOn).First(), WinnerCount = ( from winner in MetaData.Winner where objectiveIds.Contains(winner.ObjectiveID) where winner.Active where winner.UserID == up.UserID orderby winner.CreatedOn descending select winner).Count(), Video1 = ( from winner in MetaData.Winner join o in MetaData.Objective on winner.ObjectiveID equals o.ObjectiveID where o.ObjectiveNm == Constants.Promotions.SecVideo1 where winner.Active where winner.UserID == up.UserID select winner).Count(), Quiz1 = ( from winner2 in MetaData.Winner join o2 in MetaData.Objective on winner2.ObjectiveID equals o2.ObjectiveID where o2.ObjectiveNm == Constants.Promotions.SecQuiz1 where winner2.Active where winner2.UserID == up.UserID select winner2).Count(), }; </code></pre>

1428

<p>The following working function seems a bit hacky to me as it has been pieced together from a handful of (probably poorly written) online tutorials, and I want to know if there is a better (or more standard) way to approach this.</p> <pre><code>/*** * GET HTTP Operation * * @param request Request URI * @return Element Root Element of XML Response */ protected Element get(String request) { HttpURLConnection connection = null; Element rootElement; try { URL url = new URL(this.baseUrl + request); connection = (HttpURLConnection) url.openConnection(); connection.setRequestMethod("GET"); BASE64Encoder enc = new sun.misc.BASE64Encoder(); String userpassword = this.username + ":" + this.password; String encodedAuthorization = enc.encode( userpassword.getBytes() ); connection.setRequestProperty("Authorization", "Basic "+ encodedAuthorization); connection.setRequestProperty("Content-type", "application/xml"); connection.setRequestProperty("Accept", "application/xml"); InputStream responseStream = connection.getInputStream(); //--- Parse XML response InputStream into DOM DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); Document doc = db.parse(responseStream); rootElement = doc.getDocumentElement(); } catch(Exception e) { System.out.print(e.toString()); rootElement = null; } finally { if(connection != null) { connection.disconnect(); } } return rootElement; } </code></pre> <p>I am a Java novice and am especially unclear on proper <code>try</code>/<code>catch</code> usage.</p> <p>I am creating a Java Wrapper for an REST API and this is a small piece of that puzzle. You can <a href="https://github.com/jondavidjohn/java-basecamp-api-wrapper" rel="nofollow">click here</a> to see a bigger picture of the project as a whole.</p>

1430

<p>The program finds the non repeated number in a <code>int</code> array. I am using a <code>count</code> for the duplicates and making a <code>Numcounts[]</code> to store the count values. I am assuming the array is sorted. Then I can check the <code>Numcounts[]</code> for <code>1</code>, and that would be the non-repeating number. The complexity is \$O(n^2)\$.</p> <p>Can you tell me how to do the same thing using hashmaps? I haven't used hashmaps and I know the complexity can be reduced to \$O(n))\$ using them.</p> <pre><code>#include&lt;stdafx.h&gt; #include&lt;stdio.h&gt; int main() { int n=6; int * Numcounts = new int[n]; int count = 0; int a[6] = {1,1,1,2,2,3}; // sort the array before proceeding.Because in the else part count is set to zero. //If the array is unsorted then count will be reset in middle and will not retain the previous count. for(int i=0;i&lt;n;i++) { for(int j=0;j&lt;n;j++) { if(a[i]==a[j]) { count = count+1; Numcounts[i] = count; } else{ count = 0; } } } } </code></pre>

1434

<p>I have this for loop for creating a list of variables:</p> <pre><code>vars &lt;- c( 'beta.o', 'sd.y') for (x in c('ghs', 'site', 'trt')) { if(model.parms[[x]] == 1) { data &lt;- data[, which(names(data) != x)] } else { data &lt;- data if(x!='ghs') { vars &lt;- c(vars, paste('sd.', x, sep = '')) } m &lt;- min(model.parms[[x]], 5) for (i in 1:m) { if(i == 1 &amp;&amp; x == 'site') { vars &lt;- c(vars, 'beta.site[1]') } if (i &gt; 1) { vars &lt;- c(vars, paste('beta.', x, '[', i, ']', sep='')) } } } } </code></pre> <p>It has been bothering me terribly, and I have failed the last two times I have tried to replace it, although conceptually it should be able to be written in a few lines. Any advice?</p>

1437

<blockquote> <p>A function f is defined by the rule that f(n) = n if n &lt; 3 and f(n) = f(n-1) + 2f(n-2) + 3f(n-3) if n>=3. Write a recursive and an iterative process for computing f(n).</p> </blockquote> <p>I wrote the following:</p> <pre><code>(define (f_r n) ; recursive (cond ((&lt; n 3) n) (else (+ (f_r (- n 1)) (* 2 (f_r (- n 2))) (* 3 (f_r (- n 3))))))) (define (f_i n) ;iterative (f_i-prime 1 0 0 n)) (define (f_i-prime n n-1 n-2 count) (cond ((= count 0) n) ((f_i-prime (+ n n-1 n-2) (+ n n-1) n-1 (- count 1))))) </code></pre> <p>What do you think?</p> <p><strong>EDIT 1:</strong> Since my first iterative solution was erroneous, here is a corrected version:</p> <pre><code>(define (f_i n) ;iterative (f_i-prime 2 1 0 n)) (define (f_i-prime f_x+2 f_x+1 f_x n-x) (cond ((= n-x 0) f_x) ((f_i-prime (+ f_x+2 (* 2 f_x+1) (* 3 f_x) ) f_x+2 f_x+1 (- n-x 1))))) </code></pre>

1440

<blockquote> <pre><code> 1 1 1 1 2 1 1 3 3 1 </code></pre> </blockquote> <p>What do you think of this solution for computing Pascal's triangle?</p> <pre><code>(define (pascal row column) (cond ((or (= row column) (= 1 column)) 1) (else (+ (pascal (- row 1) (- column 1)) (pascal (- row 1) column))))) </code></pre>

1441

<p>I've always seen the <code>IPrincipal</code> and <code>IIdentity</code> interfaces separately, but I haven't seen any compelling reason for it, so I have my own interface that combines the two:</p> <pre><code>public interface IUser : System.Security.Principal.IIdentity, System.Security.Principal.IPrincipal { string Role { get; set; } } </code></pre> <p>Then I implement the interface as:</p> <pre><code>public class User : IUser { public string Role { get; set; } public System.Security.Principal.IIdentity Identity { get { return this; } } public string AuthenticationType { get { throw new System.NotImplementedException(); } } public bool IsAuthenticated { get { throw new System.NotImplementedException(); } } public string Name { get { throw new System.NotImplementedException(); } } public bool IsInRole(string role) { throw new System.NotImplementedException(); } } </code></pre> <p>Does this <a href="http://en.wikipedia.org/wiki/Code_smell" rel="nofollow">smell</a>? Do I have a security issue here?</p>

1442

<p>From SICP's 1.24: (<a href="http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-11.html" rel="nofollow">Exponentiation</a>) </p> <p>(you may need to click through and read ~1 page to understand)</p> <blockquote> <p>Exercise 1.16. Design a procedure that evolves an iterative exponentiation process that uses successive squaring and uses a logarithmic number of steps, as does fast-expt. (Hint: Using the observation that (<em>b</em>^<em>n</em>/2)² = (<em>b</em>²)^<em>n</em>/2, keep, along with the exponent <em>n</em> and the base <em>b</em>, an additional state variable <em>a</em>, and define the state transformation in such a way that the product <em>a bⁿ</em> is unchanged from state to state. At the beginning of the process <em>a</em> is taken to be 1, and the answer is given by the value of <em>a</em> at the end of the process. In general, the technique of defining an invariant quantity that remains unchanged from state to state is a powerful way to think about the design of iterative algorithms.)</p> </blockquote> <p>I wrote the following solution:</p> <pre><code>(define (even n) (= (remainder n 2) 0)) (define (fast-expt b n) (fast-expt-iter b b n)) (define (fast-expt-iter a b n) (cond ((= n 1) a) ((even n) (fast-expt-iter (* a b) b (/ n 2))) (else (fast-expt-iter (* a b) b (- n 1))))) </code></pre> <p>Do you think my solution is correct? Moreover, what do you think about my code?</p>

1443

<p>Given the following task:</p> <blockquote> <p><strong>Exercise 1.17</strong></p> <p>The exponentiation algorithms in this section are based on performing exponentiation by means of repeated multiplication. In a similar way, one can perform integer multiplication by means of repeated addition. The following multiplication procedure (in which it is assumed that our language can only add, not multiply) is analogous to the expt procedure:</p> <pre><code>(define (* a b) (if (= b 0) 0 (+ a (* a (- b 1))))) </code></pre> <p>This algorithm takes a number of steps that is linear in b. Now suppose we include, together with addition, operations double, which doubles an integer, and halve, which divides an (even) integer by 2. Using these, design a multiplication procedure analogous to fast-expt that uses a logarithmic number of steps.</p> </blockquote> <p>I wrote this solution:</p> <pre><code>(define (double a) (* a 2)) (define (halve a) (/ a 2)) (define (even n) (= (remainder n 2) 0)) (define (times a b) (cond ((= 1 b) a) ((even b) (times (double a) (halve b))) (else (times (+ a a) (- b 1))))) </code></pre> <p>What do you think?</p>

1444

<p>Just thinking if using code like this</p> <pre><code>&lt;?php abstract class helper { private static $_cycles = array(); public static function isOdd($v) { return (0 == ($v % 2)) ? false: true; } public static function isEven($v) { return !self::isOdd($v); } public static function cycle($odd, $even) { $trace = debug_backtrace(); $trace = $trace[0]; $cycle = crc32(serialize($trace)); if (!isset(self::$_cycles[$cycle])) { self::$_cycles[$cycle] = 1; } return (self::isOdd(self::$_cycles[$cycle]++)) ? $odd : $even; } } </code></pre> <p>for featues like this</p> <pre><code>&lt;?php foreach ($data as $record): ?&gt; &lt;p class="&lt;?php echo helper::cycle('oddCss', 'evenCss'); ?&gt;"&gt;&lt;?php echo $record; ?&gt;&lt;/p&gt; &lt;?php endforeach; ?&gt; </code></pre> <p>is not overcoded</p> <p>PS<br> Easy of usage (by html/css coders) is more important then performance in this particular case</p> <p>UPDATE:<br> As @Geoffrey mentioned i didn't tell before that same 'oddCss', 'evenCss' pair may be used several times on one page (so basically within one request)</p>

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<p>I am relatively new to JavaScript and JQuery. I wanted a Datepicker that has the following functionality:</p> <ol> <li>Weekends are not selectable </li> <li>Non working days (bank holidays etc.) are not selectable </li> <li>The first selectable day must be x number of full working days in the future, taking into account bank holidays and weekends </li> </ol> <p>I looked at few examples and came up with this (the date format is dd/mm):</p> <pre><code>$(function() { var holidays= [[3,1], [22,4], [25,4], [29,4], [2,5], [30,5], [29,8], [26,12], [27,12]]; var workingDayOffset = 10, selectedDate = new Date(); function nonWorkingDays(date) { for (var j = 0; j &lt; holidays.length; j++) { if (date.getMonth() == holidays[j][1] - 1 &amp;&amp; date.getDate() == holidays[j][0]) { return [false, '']; } } return [true, '']; } function beforeCurrentDate(date) { if(date.getDate() === selectedDate.getDate() &amp;&amp; date.getMonth() === selectedDate.getMonth() &amp;&amp; date.getFullYear() === selectedDate.getFullYear()) { return [true, '']; } return [date &lt; selectedDate,'']; } function nonAvailableDays(date) { var noWeekend = $.datepicker.noWeekends(date), before = beforeCurrentDate(date), holiday = nonWorkingDays(date); return [noWeekend[0] &amp;&amp; before[0] &amp;&amp; holiday[0], '']; } for(var i = 0; i &lt; workingDayOffset; i++) { selectedDate.setDate(selectedDate.getDate() + 1); if(!nonAvailableDays(selectedDate)[0]) { i--; } } Date.prototype.formatDDMMYY=function(){ var dd = this.getDate(), mm = this.getMonth()+1, yyyy = this.getFullYear(); if(dd&lt;10){ dd = '0' + dd; } if(mm&lt;10){ mm = '0'+ mm; } return String(dd + "\/" + mm + "\/" + yyyy); }; $( "#datepicker" ).val(selectedDate.formatDDMMYY()); $( "#datepicker" ).datepicker({ beforeShowDay: nonAvailableDays, dateFormat: 'dd/mm/yy', showOn: 'button', buttonText: "select", defaultDate: selectedDate,gotoCurrent: true}) ; }); </code></pre> <p>I am looking for a general critique of the code, but also there are a couple of things that I thought would be easier / cleaner:</p> <ol> <li><p>In beforeCurrentDate I wanted to do a check that the date was less than selectedDate, in terms of the whole date, not including the time component. Using <code>date &gt; selectedDate</code> would return <code>false</code> even if the date component was the same, due to the time part. I thought about setting the time on the selected date, but then GMT offset came into play. It seemed to me that it should be easier, in the end I added a fudge that check just the date components for a match.</p></li> <li><p>I am not sure adding <code>Date.prototype.formatDDMMYY</code> is the right way to go. Again, this felt like it should be more straight forward.</p></li> </ol> <p>I am interested to hear your thoughts on this.</p>

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<p>I created a few forms for faculty members to nominate colleagues for awards. Many of the nominations require documentation to be submitted in order to validate the nomination. I created one form then modified it to fit the needs of many different award forms. I created it rather hastily and would like input as to how I may trim the fat and make the code more efficient.</p> <p>One of the forms can be found <a href="http://pastebin.com/EuWERS4B" rel="nofollow">here</a>. Here's the code relevant to file uploading (starting at line 376 of the paste):</p> <pre><code>&lt;!---Set file upload destination path to nominationUploads/firstname_lastname---&gt; &lt;cfset destination = expandPath("./nominationUploads/#fname#_#lname#/")&gt; &lt;!---If the destination directory does not exist, create it. This will be unique for each nominee.---&gt; &lt;cfif not directoryExists(destination)&gt; &lt;cfdirectory action="create" directory="#destination#"&gt; &lt;/cfif&gt; &lt;!---Upload document to the destination. Accept only MSWord, PDF, RTF and plain text files.---&gt; &lt;cffile action="upload" filefield="nominationLetter" accept="application/msword, application/pdf, application/rtf, text/plain, application/vnd.ms-word.document.12, application/vnd.openxmlformats-officedocument.wordprocessingml.document" destination="#destination#" nameconflict="makeunique"&gt; &lt;!--- Create variable to reference the original document name and extension uploaded from client.---&gt; &lt;cfset clientNominationLetter = #file.ClientFile#&gt; &lt;!---Create variable to reference renamed document. Retain orignal file extension.---&gt; &lt;cfset renameNomination = "nominationLetter"&amp;"."&amp;#cffile.clientFileExt#&gt; &lt;!---Rename uploaded document using variable. Save renamed document to original destination.---&gt; &lt;cffile action="rename" source="#destination##File.ServerFile#" destination="#destination##Trim(renameNomination)#"&gt; &lt;!---Upload document to the destination. Accept only MSWord, PDF, RTF and plain text files.---&gt; &lt;cffile action="upload" filefield="curriculumVita" accept="application/msword, application/pdf, application/rtf, text/plain, application/vnd.ms-word.document.12, application/vnd.openxmlformats-officedocument.wordprocessingml.document" destination="#destination#" nameconflict="makeunique"&gt; &lt;!--- Create variable to reference the original document name and extension uploaded from client.---&gt; &lt;cfset clientCurriculumVita = #file.ClientFile#&gt; &lt;!---Create variable to reference renamed document. Retain orignal file extension.---&gt; &lt;cfset renameCurriculumVita = "curriculumVita"&amp;"."&amp;#cffile.clientFileExt#&gt; &lt;!---Rename uploaded document using variable. Save renamed document to original destination.---&gt; &lt;cffile action="rename" source="#destination##File.ServerFile#" destination="#destination##Trim(renameCurriculumVita)#"&gt; &lt;!---Upload document to the destination. Accept only MSWord, PDF, RTF and plain text files.---&gt; &lt;cffile action="upload" filefield="recommendation" accept="application/msword, application/pdf, application/rtf, text/plain, application/vnd.ms-word.document.12, application/vnd.openxmlformats-officedocument.wordprocessingml.document" destination="#destination#" nameconflict="makeunique"&gt; &lt;!--- Create variable to reference the original document name and extension uploaded from client.---&gt; &lt;cfset clientRecommendation = #file.ClientFile#&gt; &lt;!---Create variable to reference renamed document. Retain orignal file extension.---&gt; &lt;cfset renameRecommendation = "recommendation"&amp;"."&amp;#cffile.clientFileExt#&gt; &lt;!---Rename uploaded document using variable. Save renamed document to original destination.---&gt; &lt;cffile action="rename" source="#destination##File.ServerFile#" destination="#destination##Trim(renameRecommendation)#"&gt; &lt;cfif Len(form.recommendation2)&gt; &lt;!---Upload document to the destination. Accept only MSWord, PDF, RTF and plain text files.---&gt; &lt;cffile action="upload" filefield="recommendation2" accept="application/msword, application/pdf, application/rtf, text/plain, application/vnd.ms-word.document.12, application/vnd.openxmlformats-officedocument.wordprocessingml.document" destination="#destination#" nameconflict="makeunique"&gt; &lt;!--- Create variable to reference the original document name and extension uploaded from client.---&gt; &lt;cfset clientRecommendation2 = #file.ClientFile#&gt; &lt;!---Create variable to reference renamed document. Retain orignal file extension.---&gt; &lt;cfset renameRecommendation2 = "recommendation2"&amp;"."&amp;#cffile.clientFileExt#&gt; &lt;!---Rename uploaded document using variable. Save renamed document to original destination.---&gt; &lt;cffile action="rename" source="#destination##File.ServerFile#" destination="#destination##Trim(renameRecommendation2)#"&gt; &lt;/cfif&gt; &lt;cfif Len(form.recommendation3)&gt; &lt;!---Upload document to the destination. Accept only MSWord, PDF, RTF and plain text files.---&gt; &lt;cffile action="upload" filefield="recommendation3" accept="application/msword, application/pdf, application/rtf, text/plain, application/vnd.ms-word.document.12, application/vnd.openxmlformats-officedocument.wordprocessingml.document" destination="#destination#" nameconflict="makeunique"&gt; &lt;!--- Create variable to reference the original document name and extension uploaded from client.---&gt; &lt;cfset clientRecommendation3 = #file.ClientFile#&gt; &lt;!---Create variable to reference renamed document. Retain orignal file extension.---&gt; &lt;cfset renameRecommendation3 = "recommendation3"&amp;"."&amp;#cffile.clientFileExt#&gt; &lt;!---Rename uploaded document using variable. Save renamed document to original destination.---&gt; &lt;cffile action="rename" source="#destination##File.ServerFile#" destination="#destination##Trim(renameRecommendation3)#"&gt; &lt;/cfif&gt; &lt;cfif Len(form.recommendation4)&gt; &lt;!---Upload document to the destination. Accept only MSWord, PDF, RTF and plain text files.---&gt; &lt;cffile action="upload" filefield="recommendation4" accept="application/msword, application/pdf, application/rtf, text/plain, application/vnd.ms-word.document.12, application/vnd.openxmlformats-officedocument.wordprocessingml.document" destination="#destination#" nameconflict="makeunique"&gt; &lt;!--- Create variable to reference the original document name and extension uploaded from client.---&gt; &lt;cfset clientRecommendation4 = #file.ClientFile#&gt; &lt;!---Create variable to reference renamed document. Retain orignal file extension.---&gt; &lt;cfset renameRecommendation4 = "recommendation4"&amp;"."&amp;#cffile.clientFileExt#&gt; &lt;!---Rename uploaded document using variable. Save renamed document to original destination.---&gt; &lt;cffile action="rename" source="#destination##File.ServerFile#" destination="#destination##Trim(renameRecommendation4)#"&gt; &lt;/cfif&gt; &lt;cfif Len(form.recommendation5)&gt; &lt;!---Upload document to the destination. Accept only MSWord, PDF, RTF and plain text files.---&gt; &lt;cffile action="upload" filefield="recommendation5" accept="application/msword, application/pdf, application/rtf, text/plain, application/vnd.ms-word.document.12, application/vnd.openxmlformats-officedocument.wordprocessingml.document" destination="#destination#" nameconflict="makeunique"&gt; &lt;!--- Create variable to reference the original document name and extension uploaded from client.---&gt; &lt;cfset clientRecommendation5 = #file.ClientFile#&gt; &lt;!---Create variable to reference renamed document. Retain orignal file extension.---&gt; &lt;cfset renameRecommendation5 = "recommendation5"&amp;"."&amp;#cffile.clientFileExt#&gt; &lt;!---Rename uploaded document using variable. Save renamed document to original destination.---&gt; &lt;cffile action="rename" source="#destination##File.ServerFile#" destination="#destination##Trim(renameRecommendation5)#"&gt; &lt;/cfif&gt; &lt;cfif Len(form.recommendation6)&gt; &lt;!---Upload document to the destination. Accept only MSWord, PDF, RTF and plain text files.---&gt; &lt;cffile action="upload" filefield="recommendation6" accept="application/msword, application/pdf, application/rtf, text/plain, application/vnd.ms-word.document.12, application/vnd.openxmlformats-officedocument.wordprocessingml.document" destination="#destination#" nameconflict="makeunique"&gt; &lt;!--- Create variable to reference the original document name and extension uploaded from client.---&gt; &lt;cfset clientRecommendation6 = #file.ClientFile#&gt; &lt;!---Create variable to reference renamed document. Retain orignal file extension.---&gt; &lt;cfset renameRecommendation6 = "recommendation6"&amp;"."&amp;#cffile.clientFileExt#&gt; &lt;!---Rename uploaded document using variable. Save renamed document to original destination.---&gt; &lt;cffile action="rename" source="#destination##File.ServerFile#" destination="#destination##Trim(renameRecommendation6)#"&gt; &lt;/cfif&gt; &lt;/cfif&gt; </code></pre>

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<p>As much as I try, I cannot seem to get this Coffeescript code to look beautiful (I'd like to think it is possible). I have tried both Javascript and Coffeescript. Just to be clear, this code works fine, but it is hard to read, for reasons that I am unable to pinpoint.</p> <p><strong>How can it be refactored, reorganized, and what changes to coding style can be made to make it more appealing to read?</strong></p> <pre><code>define [ "plugins/ui/ui", "./js/highlight" ], (ui, highlight) -&gt; editor = {} jQuery ($) -&gt; # A widget to view source code. $.widget 'core.editor', _create: -&gt; $editor = $(this.element) $editor .addClass('editor') .append($('&lt;ul spellcheck="false" contenteditable&gt; &lt;li&gt;&lt;/li&gt; &lt;/ul&gt;')) # Move the gutter along with the editable area. this.lines().bind 'scroll', (event) -&gt; $this = $(this) $this.siblings(".gutter").css(top: $this.scrollTop() * -1) # Highlight the sourceview using the given language. # The language's JSON rule file is loaded. highlight: (language) -&gt; this.language = language require ["text!plugins/editor/js/#{ language }.json"], (json) =&gt; this._rules = JSON.parse(json) return # Update the `left` of the `&lt;ul&gt;` based on the gutter width. # Each time the number of digits in the gutter changes, it becomes wider or # narrower, and the editor needs the shift accordingly. updateGutterWidth: () -&gt; # The `8` is the gutter's left padding. this.lines().css(left: this.gutter().width() + 8) # Add or remove line numbers if the number of lines has changed. # `change` is a modification the the line count (In case the character was not yet # typed). updateLineNumbers: (change = 0) -&gt; $gutter = this.gutter() count = this.lines().children("li").length current = $gutter.children("span").length count += change # Add lines if (count &gt; current) for i in [current..(count - 1)] ele = document.createElement("span") ele.innerText = "#{ i + 1 }" $gutter[0].appendChild(ele) # Remove lines else if (current &gt; count) for j in [count..(current - 1)] $gutter.children("span:last-child").remove() this.updateGutterWidth() if current != count return # Set whether or not the gutter should be visible. lineNumbers: (bool) -&gt; if bool == true and !this.number $(this.element) .prepend('&lt;div class="gutter"&gt;&lt;/div&gt;') this.lines() .css(left: 20) this.updateLineNumbers() else if bool == false and this.number this.gutter().remove() $(this.element) .css(left: 1) this.number = bool # Return the gutter (a jQuery object). gutter: () -&gt; this._gutter ?= $(this.element).children("div.gutter") return this._gutter # Return a jQuery `&lt;ul&gt;`. Each `&lt;li&gt;` is a line of the source viewer. lines: -&gt; return $(this.element).children('ul') # A hash of syntax highlighting rules. rules: -&gt; return this._rules # Re-highlight the text. $(".editor &gt; ul").live 'keyup', (event) -&gt; # 13: Enter # 37, 38, 39, 40: Arrow Keys # 33, 34: Page up / down # 16, 17, 18, 91: Shift, Ctrl, Alt, Meta # 35, 36: Home / end if !(event.which in [13, 37, 38, 39, 40, 33, 34, 16, 17, 18, 91, 35, 36]) and !event.altKey and !event.ctrlKey # Prevent an annoying error when backspacing to the beginning of a line. selection = window.getSelection() # Store the cursor position before highlighting. cursorPos = selection.getRangeAt(0) if cursorPos.getClientRects()[0] clickx = cursorPos.getClientRects()[0].left clicky = cursorPos.getClientRects()[0].top # Highlight $li = $(selection.focusNode).closest("li") rules = $li.closest(".editor").editor('rules') highlight.highlight($li, rules) # Restore cursor position. cursorPos = document.caretRangeFromPoint(clickx, clicky) window.getSelection().addRange(cursorPos) # Line numbering update. $(".editor &gt; ul").live 'keydown', (event) -&gt; # Redo line numbering for Enter, Backspace, Delete. if (event.which in [13, 8, 46]) $this = $(this) newline = switch event.which when 13 then 1 when 8 then -1 else 0 $this.parent().editor('updateLineNumbers', newline) # Correction setTimeout(() -&gt; $this.parent().editor('updateLineNumbers', 0) , 300) # ##################### MAIN ########################## $(".frame").frame('tabs').last().tab("content") .append("&lt;div id='sourceview'&gt;&lt;/div&gt;") $("#sourceview") .css position: 'absolute' left: 1 right: 1 top: 1 bottom: 1 .editor() .editor('theme', 'plugins/editor/themes/idlefingers.css') .editor("highlight", "javascript") .editor("lineNumbers", true) return editor </code></pre>

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<p>This code comes from a <a href="http://wordpress.org/support/topic/plugin-vote-it-up-show-top-voted-post-in-index-page" rel="nofollow">Wordpress plugin's forum</a> called Vote it Up. It sort posts by vote. A lotof people say that there is more code than is needed. So I was wondering if someone have any idea about how to clean it a bit.</p> <p><strong>votingfunctions.php:</strong></p> <pre><code>function ShowPostByVotes() { global $wpdb, $voteiu_databasetable; mysql_connect(DB_HOST, DB_USER, DB_PASSWORD) or die(mysql_error()); mysql_select_db(DB_NAME) or die(mysql_error()); //Set a limit to reduce time taken for script to run $upperlimit = get_option('voteiu_limit'); if ($upperlimit == '') { $upperlimit = 100; } $lowerlimit = 0; $votesarray = array(); $querystr = " SELECT * FROM $wpdb-&gt;posts WHERE post_status = 'publish' AND post_type = 'post' ORDER BY post_date DESC "; $pageposts = $wpdb-&gt;get_results($querystr, OBJECT); //Use wordpress posts table //For posts to be available for vote editing, they must be published posts. mysql_connect(DB_HOST, DB_USER, DB_PASSWORD) or die(mysql_error()); mysql_select_db(DB_NAME) or die(mysql_error()); //Sorts by date instead of ID for more accurate representation $posttablecontents = mysql_query("SELECT ID FROM ".$wpdb-&gt;prefix."posts WHERE post_type = 'post' AND post_status = 'publish' ORDER BY post_date_gmt DESC LIMIT ".$lowerlimit.", ".$upperlimit."") or die(mysql_error()); $returnarray = array(); while ($row = mysql_fetch_array($posttablecontents)) { $post_id = $row['ID']; $vote_array = GetVotes($post_id, "array"); array_push($votesarray, array(GetVotes($post_id))); } array_multisort($votesarray, SORT_DESC, $pageposts); $output = $pageposts; return $output; } </code></pre> <p><strong>index.php:</strong></p> <p> <pre><code>$pageposts = ShowPostByVotes(); ?&gt; &lt;?php if ($pageposts): ?&gt; &lt;?php foreach ($pageposts as $post): ?&gt; &lt;?php setup_postdata($post); ?&gt; </code></pre> <p>Attention! Code above is something like:</p> <pre><code>&lt;?php if (have_posts()) : ?&gt; &lt;?php while (have_posts()) : the_post(); ?&gt; </code></pre> <p>so in foreach loop you can use statements like in standard "The Loop" for example the_content, the_time(). To end this add</p> <pre><code>&lt;?php endforeach; ?&gt; &lt;?php else : ?&gt; &lt;h2 class="center"&gt;Not Found&lt;/h2&gt; &lt;p class="center"&gt;Sorry, but you are looking for something that isn't here.&lt;/p&gt; &lt;?php include (TEMPLATEPATH . "/searchform.php"); ?&gt; &lt;?php endif; ?&gt; </code></pre> <p><strong>EDIT:</strong></p> <p>How I run a custom loop:</p> <pre><code> &lt;?php $custom_posts = new WP_Query(); ?&gt; &lt;?php $custom_posts-&gt;query('category_name=Pictures'); ?&gt; &lt;?php while ($custom_posts-&gt;have_posts()) : $custom_posts-&gt;the_post(); ?&gt; &lt;div class="content-block-2"&gt; &lt;a href="&lt;?php the_permalink(); ?&gt;" title="&lt;?php printf( esc_attr__( 'Permalink to %s', 'twentyten' ), the_title_attribute( 'echo=0' ) ); ?&gt;" rel="bookmark"&gt;&lt;?php the_content(); ?&gt;&lt;/a&gt; &lt;/div&gt; &lt;?php endwhile; ?&gt; </code></pre>

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<p>I've been experimenting with Perl and MySql and wrote this code for connecting and writing to a database:</p> <pre><code># MySQL DDL to create database used by code # # CREATE DATABASE sampledb; # # USE sampledb; # # CREATE TABLE `dbtable` ( # `id` int(11) NOT NULL AUTO_INCREMENT, # `demo` longtext, # PRIMARY KEY (`id`) # ) ENGINE=InnoDB DEFAULT CHARSET=utf8; # PERL MODULES use strict; use warnings; use DBI; #http://dbi.perl.org # CONFIG VARIABLES my $platform = "mysql"; my $database = "sampledb"; my $host = "localhost"; my $port = "3306"; my $username = "root"; my $password = "password"; # DATA SOURCE NAME my $dsn = "dbi:$platform:$database:$host:$port"; # PERL DBI CONNECT my $connect = DBI-&gt;connect($dsn, $username, $password); # VARS for Examples my $query; my $query_handle; my $id; my $demo; # Example 1 using prepare() and execute() INSERT # SAMPLE VARIABLE AND VALUES TO PASS INTO SQL STATEMENT $id = 1; $demo = "test"; # INSERT $query = "INSERT INTO dbtable (id, demo) VALUES ('$id', '$demo')"; $query_handle = $connect-&gt;prepare($query); $query_handle-&gt;execute(); undef $query; # Example 2 using do() UPDATE # SAMPLE VARIABLE AND VALUES TO PASS INTO SQL STATEMENT $id = 1; $demo = "test 2"; # UPDATE $query = "UPDATE dbtable SET demo = '$demo' WHERE id = $id"; $query_handle = $connect-&gt;do($query); undef $query; </code></pre> <p>Is this the correct/idiomatic way to access a database in Perl? Are there any other improvements I could make?</p>

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<p>This is a collection of reasonably useful functions I put together for writing my blog.</p> <pre><code>(require 'htmlize) (defvar blog-mode-map nil "Keymap for blog minor mode") (unless blog-mode-map (let ((map (make-sparse-keymap))) (define-key map "\C-cl" 'insert-link) (define-key map "\C-cp" 'insert-code-block) (define-key map "\C-cc" 'insert-inline-code) (define-key map "\C-cb" 'insert-bold) (define-key map "\C-cq" 'insert-quote) (define-key map "\C-cs" 'insert-sig) (define-key map "\C-cf" 'insert-footnote) (define-key map "\C-c\C-l" 'region-to-link) (define-key map "\C-c\C-p" 'region-to-code-block) (define-key map "\C-c\C-c" 'region-to-inline-code) (define-key map "\C-c\C-b" 'region-to-bold) (define-key map "\C-c\C-q" 'region-to-quote) (define-key map "\C-c\C-s" 'region-to-sig) (define-key map "\C-c\C-f" 'region-to-footnote) (define-key map "/" 'smart-backslash) (setq blog-mode-map map))) (define-minor-mode blog-mode "This is a collection of useful keyboard macros for editing Langnostic" nil " Blog" (use-local-map blog-mode-map)) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; simple definitions (defun insert-tag (start-tag &amp;optional end-tag) "Inserts a tag at point" (interactive) (insert start-tag) (save-excursion (insert (or end-tag "")))) (defun wrap-region (start end start-tag &amp;optional end-tag) "Inserts end tag at the end of the region, and start tag at point" (goto-char end) (insert (or end-tag "")) (goto-char start) (insert start-tag)) (defmacro definsert (tag-name start-tag end-tag) "Defines insert function." `(defun ,(make-symbol (concat "insert-" (symbol-name tag-name))) () (interactive) (insert-tag ,start-tag ,end-tag))) (defmacro defregion (tag-name start-tag end-tag) "Defines region wrapper function." `(defun ,(make-symbol (concat "region-to-" (symbol-name tag-name))) () (interactive) (wrap-region (region-beginning) (region-end) ,start-tag ,end-tag))) (definsert link (concat "&lt;a href=\"" (x-get-clipboard) "\"&gt;") "&lt;/a&gt;") (defregion link (concat "&lt;a href=\"" (x-get-clipboard) "\"&gt;") "&lt;/a&gt;") (definsert bold "&lt;b&gt;" "&lt;/b&gt;") (defregion bold "&lt;b&gt;" "&lt;/b&gt;") (definsert quote "&lt;blockquote&gt;" "&lt;/blockquote&gt;") (defregion quote "&lt;blockquote&gt;" "&lt;/blockquote&gt;") (definsert sig "&lt;span class=\"sig\"&gt;" "&lt;/span&gt;") (defregion sig "&lt;span class=\"sig\"&gt;" "&lt;/span&gt;") ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; &lt;pre&gt; and &lt;code&gt; definitions (definsert code-block "&lt;pre&gt;" "&lt;/pre&gt;") (definsert inline-code "&lt;code&gt;" "&lt;/code&gt;") ;; region versions are more complicated to accomodate htmlize (defun region-to-inline-code () "HTMLize just the current region and wrap it in a &lt;code&gt; block" (interactive) (let((htmlified (substring (htmlize-region-for-paste (region-beginning) (region-end)) 6 -6))) (delete-region (region-beginning) (region-end)) (insert-inline-code) (insert htmlified))) (defun region-to-code-block () "HTMLize the current region and wrap it in a &lt;pre&gt; block" (interactive) (let ((htmlified (htmlize-region-for-paste (region-beginning) (region-end)))) (delete-region (region-beginning) (region-end)) (insert (concat "&lt;pre&gt;" (substring htmlified 6))))) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; footnote definitions (defun insert-footnote () "Inserts footnote, and a return link at the bottom of the file. Moves point to footnote location." (interactive) (progn (footnotes-header) (let ((footnote-name (format-time-string "%a-%b-%d-%H%M%S%Z-%Y" (current-time)))) (insert "&lt;a href=\"#foot-" footnote-name "\" name=\"note-" footnote-name "\"&gt;[note]&lt;/a&gt;") (goto-char (point-max)) (insert "\n\n&lt;a href=\"#note-" footnote-name "\" name=\"foot-" footnote-name "\"&gt;[back]&lt;/a&gt; - ")))) (defun region-to-footnote () "Inserts a footnote at point and return link at the bottom. Moves the current region to the end of the file. Leaves point where it is." (interactive) (save-excursion (kill-region (region-beginning) (region-end)) (insert-footnote) (yank))) (defun footnotes-header () "Inserts footnote header if not already present" (unless (save-excursion (search-forward "&lt;hr /&gt;\n&lt;h5&gt;Footnotes&lt;/h5&gt;" nil t)) (save-excursion (goto-char (point-max)) (insert "\n\n&lt;hr /&gt;\n&lt;h5&gt;Footnotes&lt;/h5&gt;")))) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; utility (defun smart-backslash () "Backslash closes previous tag when used in the combination &lt;/. Self-inserts otherwise." (interactive) (if (equal (save-excursion (backward-char) (thing-at-point 'char)) "&lt;") (progn (backward-delete-char 1) (sgml-close-tag)) (insert "/"))) (provide 'blog-mode) </code></pre> <p>I'd like some advice on how to remove duplication in a few obvious places. To my mind, I should be able to do something like <code>(deftag bold "b" "&lt;b&gt;" "&lt;/b&gt;")</code> which would expand into a <code>definsert</code>, <code>defregion</code> and <code>define-key</code>. I'm not sure how to have a macro define multiple functions in Elisp though; <code>progn</code> (quoted or not) doesn't seem to help.</p> <p>Feel free to point out any components I could replace with pre-built Emacs23 functions, or anything I could do more elegantly.</p> <p>EDIT: Updated version of this code can be found <a href="https://github.com/Inaimathi/emacs-utils/blob/master/blog-mode.el">here</a>.</p>

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<p>This function changes a HashSet in the root of the class called 'commands' to a set of strings found in a file at "plugins/UC/Commands.txt" (it's what was requested by the people using the plugin). If the file doesn't exist, it copies a default file found in the zip file called "Commands.txt".</p> <p>This is a weird request, and may be too much to ask for, but I realized my code is way over complicated. If you would be so kind as to show me how best to rewrite this, I would really appreciate it. When I originally wrote this, I just let Eclipse write it itself (with all the try/catch blocks being told to me), and I haven't done much to it, so it's in disarray. </p> <pre><code>public void setComs () { Set&lt;String&gt; temp = new HashSet&lt;String&gt;(); File file = null; InputStream dflt = null; InputStreamReader dfltReader = null; FileReader fileReader = null; FileOutputStream newFile = null; BufferedReader bufferedReader = null; try { fileReader = new FileReader("plugins" + File.separator + "UC" + File.separator + "Commands.txt"); try { bufferedReader = new BufferedReader(fileReader); String line = null; while ((line = bufferedReader.readLine()) != null) { temp.add(line); } bufferedReader.close(); fileReader.close(); } catch (IOException e) { System.out.println("[UC] couldn't read Commands.txt. Setting to default"); temp.clear(); dfltReader = new InputStreamReader(this.getClass().getClassLoader().getResourceAsStream("Commands.txt")); bufferedReader = new BufferedReader(dfltReader); String line = null; try { while ((line = bufferedReader.readLine()) != null) { temp.add(line); } } catch (IOException e1) { System.out.println("[UC] Cannot read default commands file. This is a critical error. " + "Message user LRFLEW on bukkit.org if you see this"); } } finally { try { fileReader.close(); } catch (IOException e) {} } } catch (FileNotFoundException e) { System.out.println("[UC] couldn't find Commands.txt. Creating a new file with default settings"); file = new File("plugins" + File.separator + "UC"); try { file.mkdir(); file = new File("plugins" + File.separator + "UC" + File.separator + "Commands.txt"); file.createNewFile(); newFile = new FileOutputStream(file); dflt = this.getClass().getClassLoader().getResourceAsStream("Commands.txt"); byte[] buffer = new byte[dflt.available()]; for (int i = 0; i != -1; i = dflt.read(buffer)) { newFile.write(buffer, 0, i); } temp.clear(); dfltReader = new InputStreamReader(dflt); bufferedReader = new BufferedReader(dfltReader); String line = null; while ((line = bufferedReader.readLine()) != null) { temp.add(line); } dflt.close(); dfltReader.close(); bufferedReader.close(); } catch (IOException e1) { System.out.println("[UC] cannot make new file. " + "Either I don't have enough permissions to see the file or you need to change the permissions of the folder. " + "Loading default settings..."); dfltReader = new InputStreamReader(this.getClass().getClassLoader().getResourceAsStream("Commands.txt")); bufferedReader = new BufferedReader(dfltReader); String line = null; try { while ((line = bufferedReader.readLine()) != null) { temp.add(line); } } catch (IOException e2) { System.out.println("[UC] Cannot read default file. This is a critical error. " + "Message user LRFLEW on bukkit.org if you see this"); } } } this.commands = temp; } </code></pre>

1468

<p>I'm cleaning build directories produced by GNOME build tool, <a href="http://live.gnome.org/Jhbuild" rel="nofollow">JHBuild</a>. This tool either downloads tarballs or clones git repositories, depending on set-up. After that, it proceeds to compilation (and then installation). Once in a while, something gets screwed up, and I need to clean the build directories so that I can start from scratch (because I don't know how to fix some of these problems).</p> <p>Here's how I did it, and I'd like you to tell me if it can be improved:</p> <pre><code>import os import subprocess top_level = os.path.expanduser("~/src/gnome") for filename in os.listdir(top_level): full_path = "{}/{}".format(top_level, filename) if os.path.isdir(full_path): cmd = "cd ~/src/gnome/{} &amp;&amp; git clean -dfx".format(filename) if subprocess.call(cmd, shell=True) != 0: cmd = "cd ~/src/gnome/{} &amp;&amp; make distclean".format(filename) if subprocess.call(cmd, shell=True) != 0: cmd = "cd ~/src/gnome/{} &amp;&amp; make clean".format(filename) subprocess.call(cmd, shell=True) </code></pre>

1476

<p>For an interview, I was asked to write code allocate memory for a rows*cols matrix, using a <em>single</em> <code>malloc()</code>. I want your comments about this code that I wrote:</p> <pre><code>/* Allots (in effect) space for a matrix of size rows*cols using a single malloc. The whole space allotted consists of an array of size 'rows' of float ptrs, followed by a float array of size 'rows' * 'cols'. The float ptrs 1,2.., are assigned to row no. 1, 2,.. in the matrix that follows. */ float** allotMatrix(const size_t &amp;rows, const size_t &amp;cols) { // Compute size of allotment = rows * cols floats + rows float ptrs size_t ptrsize = rows * sizeof(float*); size_t datasize = rows * cols * sizeof(float); size_t matsize = ptrsize + datasize; // Get if possible a memory allotment of this size. We use char* for convenience char* cmatrix = (char*) malloc(matsize); if (cmatrix == NULL) { fprintf(stderr, "Unable to allot memory"); exit(1); } memset((void*) cmatrix, 0, matsize); // Assign ptrs to data float** ptrstart = (float**) cmatrix; float* datastart = (float*) (cmatrix + ptrsize); for (size_t i = 0; i != rows; ++i) { *ptrstart = datastart; // Move to next ptr ++ptrstart; // .. and move to the next data row datastart += cols; } return (float**) cmatrix; } </code></pre>

1479

<p>I wrote an implementation of binary search in JavaScript earlier for kicks, but I noticed my version was significantly different than those found on Google. <a href="http://www.dweebd.com/javascript/binary-search-an-array-in-javascript/">Here</a> is an example of binary search I found on Google (copied here to combat link rot): </p> <pre><code>Array.prototype.binarySearch = function(find, comparator) { var low = 0, high = this.length - 1, i, comparison; while (low &lt;= high) { i = Math.floor((low + high) / 2); comparison = comparator(this[i], find); if (comparison &lt; 0) { low = i + 1; continue; }; if (comparison &gt; 0) { high = i - 1; continue; }; return i; } return null; }; </code></pre> <p>Most of the other implementations on Google are quite similar. But in mine, I don't subtract one from the low/high and continue from there. Instead, I divide the array in half and continue dividing the appropriate side in half until I reach the proper value. Code: </p> <pre><code>function binary_search_iterative(arr, ele) { var beginning = 0, end = arr.length, target; while (true) { target = Math.floor((beginning + end) / 2); if ((target === end || target === beginning) &amp;&amp; arr[target] !== ele) { return -1; } if (arr[target] &gt; ele) { end = target; } else if (arr[target] &lt; ele) { beginning = target; } else { return target; } } } </code></pre> <p>I wrote this recursive-style as well, but in testing I found this iterative version was faster.</p> <p>In my tests, I've found that the examples I've found on Google (though they did not include the one above, they were nearly identical) are faster on smaller arrays, but as the input size increases, mine overtakes those. Since binary searches are usually limited (?) to larger input sizes, I see this as an improvement.</p> <p>Is my thinking correct? Could this be done in an even better way? </p> <p>I also do not like this: </p> <pre><code>if ((target === end || target === beginning) &amp;&amp; arr[target] !== ele) { return -1; } </code></pre> <p>And I was curious if there is a good way to eliminate it or refactor the function where it's cleaner in general.</p>

1480

<p>This is a classic linked list problem.</p> <ol> <li>Deleting a node from linked list given the data to be deleted.</li> <li>Inserting a node in a sorted linked list.</li> </ol> <p>I saw various versions of this and here is my version. Could you check and let me know if this code is efficient?</p> <pre><code>void deletenode(struct node *&amp;first, int data) { struct node * current = first;// first will have the node after deletion struct node * prev = (node *)malloc(sizeof(node)); while(current!=NULL) { if(current-&gt;data!=data) { prev=current; current = current-&gt;next; } else { prev-&gt;next = current-&gt;next; delete current; break; } } } void insertinsortedlist(struct node *&amp; first, int data) { struct node * current = first;// first will have the node after insertion struct node * newnode = (node *)malloc(sizeof(node)); newnode-&gt;data = data; struct node * temp = (node *)malloc(sizeof(node)); while(current) { if((current-&gt;data &lt; data) &amp;&amp; (current-&gt;next-&gt;data &gt; data)) { temp = current-&gt;next; current-&gt;next = newnode; newnode-&gt;next = temp; break; } current = current-&gt;next; } } </code></pre>

1484

<p>I have built a "reset and confirm password" section on a site. It works great. I just have this suspicion that maybe it isn't the most efficient way. I am relatively new to jQuery but I can usually make things work well. I am just wanting to make sure I am doing them right. </p> <p>Any suggestions are appreciated. </p> <pre><code>/////////////// RESET PASSWORD ///////////////////// $('#reset_password').click(function reset_password(){ //Enter a password input field a button $('#new_pass_field').html('&lt;input type="text" id="new_password" name="new_password"&gt;&lt;button id="submit_new_pass"&gt;Submit New Password&lt;/button&gt;'); // Bind a click to the button $('#submit_new_pass').bind('click', function submit_new_pass (){ // When clicked get val of the new_password field. $get_val = $("#new_password").val(); // Hide the new_pass field and button so the confirm field and button can be entered. $('#new_pass_field').hide("fast").html('&lt;input type="text" id="password" name="password"&gt;&lt;button id="confirm_new_pass"&gt;Confirm New Password&lt;/button&gt;'); // Bind click to that confirm button $('#confirm_new_pass').bind('click', function confirm_new(){ // Get val of the confirm pass field $get_confirm_val = $("#password").val(); // Check valdation if 2 passwords match if($get_val == $get_confirm_val){ // If they match send to DB and encrypt. $.get(uri_base +'/AJAX/update_password/admin_users/'+$get_confirm_val+'/'+Math.random(), function(msg){ //If returns true then send msg password changed. and hide the password row. if(msg){ $("#err_password").html("Your Password has been changed.").queue(function(){ setTimeout(function(){ $("#err_password").dequeue(); }, 3000); }) $('#reset_pass_results').slideUp("slow"); $('#new_pass_field').hide("fast").html(''); }else{ // Error in the DB $("#err_password").html("There was an error. Your password was not changed."); } }); }else{ // Passwords didn't match now reset the clicks to try again and hide the error $("#err_password").html("Your Passwords didn't match!").delay(3000).fadeOut("slow"); $('#confirm_new_pass').bind('click', confirm_new); $('#reset_password').bind('click', reset_password); } return false; }); // Show the password field $('#new_pass_field').show("fast"); return false; }); // Show initial field and button. $('#reset_pass_results').slideDown("slow", function(){ $('#new_pass_field').show("fast"); }); return false; }); </code></pre>

1485

<p>I'm working on writing a scripting language with ANTLR and C++. This is my first actual move from ANTLR grammars into the C++ API, so I'd like to know if this would be a good way to structure the grammar (later I will be adding a tree parser or tree rewriting rules though).</p> <pre><code>grammar dyst; options { language = C; output = AST; ASTLabelType=pANTLR3_BASE_TREE; } program : statement*; statement : stopUsingNamespaceStm|usingNamespaceStm|namespaceDefineStm|functionStm|defineStm|assignStm|funcDefineStm|ifStm|whileStm|returnStm|breakStm|eventDefStm|eventCallStm|linkStm|classDefStm|exitStm|importStm|importOnceStm|directive; namespaceDefineStm : 'namespace' ident '{' statement* '}'; usingNamespaceStm : 'using' 'namespace' ident (',' ident)* ';'; stopUsingNamespaceStm : 'stop' 'using' 'namespace' ident (',' ident)* ';'; directive : '@' directiveId argList? ';'; directiveId : ID (':' ID)*; importOnceStm : 'import_once' expression ';'; importStm : 'import' expression ';'; exitStm : 'exit' expression? ';'; classDefStm : 'class' ident ('extends' ident (',' ident)*)? '{' (classSection|funcDefineStm|defineStm|eventDefStm)* '}'; classSection : ('public'|'private'|'protected') ':'; linkStm : 'link' ident 'to' ident (',' ident)* ';'; eventCallStm : 'call' ident (',' argList)? ';'; eventDefStm : 'event' ident '(' paramList? ')' ';'; returnStm : 'return' expression ';'; breakStm : 'break' int ';'; ifStm : 'if' '(' expression ')' '{' statement* '}'; whileStm : 'while' '(' expression ')' '{' statement* '}'; defineStm : 'global'? 'def' ident ('=' expression)? ';'; assignStm : ident '=' expression ';'; funcDefineStm : 'function' ident '(' paramList? ')' ('handles' ident (',' ident)*)? '{' statement* '}'; paramList : param (',' param)?; param : ident ('=' expression)?; functionStm : functionCall ';'; functionCall : ident '(' argList? ')'; argList : expression (',' expression)*; //Expressions! term : functionCall|value|'(' expression ')'; logic_not : ('!')* term; bit_not : ('~')* logic_not; urnary : '-'* bit_not; mult : urnary (('*'|'/'|'%') urnary)*; add : mult ('+' mult)*; relation : add (('&lt;='|'&gt;='|'&lt;'|'&gt;') add)*; equality : relation (('=='|'!=') relation)*; bit_and : equality ('&amp;' equality)*; bit_xor : bit_and ('^' bit_and)*; bit_or : bit_xor ('|' bit_xor)*; logic_and : bit_or ('&amp;&amp;' bit_or)*; logic_or : logic_and ('||' logic_and)*; expression : logic_or; value : ident|float|int|string|boolean|newObject|anonFunc|null_val; anonFunc : 'function' '(' paramList? ')' '{' statement* '}'; newObject : 'new' ident ('(' argList ')')?; ident : ID (('.'|'::') ID)*; float : FLOAT; int : INTEGER; string : STRING_DOUBLE|STRING_SINGLE; boolean : BOOL; null_val : NULL_VAL; FLOAT : INTEGER '.' INTEGER; INTEGER : DIGIT+; BOOL : 'true'|'false'; NULL_VAL : 'null'|'NULL'; STRING_DOUBLE : '"' .* '"'; STRING_SINGLE : '\'' .* '\''; ID : (LETTER|'_') (LETTER|DIGIT|'_')*; fragment DIGIT : '0'..'9'; fragment LETTER : 'a'..'z'|'A'..'Z'; NEWLINE : ('\n'|'\r'|'\t'|' ')+ {$channel = HIDDEN;}; COMMENT : '#' .* '\r'? '\n' {$channel = HIDDEN;}; MULTI_COMMENT : '/-' .* '-/' {$channel = HIDDEN;}; </code></pre> <p>If you are wondering about exactly what it is I'm using this for, you can take a look <a href="http://dev.redxdev.com/p/dyst" rel="nofollow noreferrer">here</a>.</p>

1487

<p>Here is my PHP class for solving Sudoku:</p> <p><a href="https://gist.github.com/889044" rel="nofollow">GitHub</a></p> <p><strong>Sudoku</strong></p> <pre><code>&lt;?php /** * Bootstrap file * * This is an example of how to use the SudokuSolver Class * Here the input array has been hardcoded. It could be send * as get or post in the real application. * * @author Anush Prem &lt;[email protected]&gt; * @package Solver * @subpackage Sudoku * @version 0.1 */ /** * Required Class files */ include_once "SudokuSolver.class.php"; // The application could take longer than normal php execution // time. So set the execution time limit to 0(unlimited). set_time_limit(0); // input sudoku array in the format row == col array mapping $sudoku = array( array(0,4,0,0,5,3,1,0,2), array(2,0,8,1,0,0,7,0,0), array(5,0,1,4,2,0,6,0,0), array(8,1,4,0,3,0,2,0,7), array(0,6,0,2,0,5,0,1,9), array(0,5,0,7,4,0,0,6,3), array(0,0,0,0,7,4,5,8,1), array(1,8,5,9,0,2,0,0,0), array(4,0,3,0,0,8,0,2,6) ); // create an object of SudokuSolver. $solver = new SudokuSolver(); // Pass the input sudoku to the $solver object. $solver -&gt; input ($sudoku); // Solve the sudoku and return the solved sudoku. $solved = $solver -&gt; solve (); // printing the formated input sudoku print "&lt;B&gt;Input Sudoku:&lt;/B&gt;&lt;br /&gt;"; foreach ($sudoku as $row){ foreach ($row as $col ){ print $col . "&amp;nbsp;&amp;nbsp;"; } print "&lt;br /&gt;"; } print "&lt;hr /&gt;"; // printing the formated solved sudoku. print "&lt;B&gt;Solved Sudoku:&lt;/B&gt;&lt;br /&gt;"; foreach ($solved as $row){ foreach ($row as $col ){ print $col . "&amp;nbsp;&amp;nbsp;"; } print "&lt;br /&gt;"; } ?&gt; </code></pre> <p><strong>Sudoku Solver</strong></p> <pre><code>&lt;?php /** * @author Anush Prem &lt;[email protected]&gt; * @package Solver * @subpackage Sudoku * @version 0.1 */ /** * &lt;i&gt;Sudoku Solver&lt;/i&gt; class * * This class solves the sudoku in my own logic. * * This solver takes time to execute according to the * complexity of the sudoku. * * @author Anush Prem &lt;[email protected]&gt; * @package Solver * @subpackage Sudoku * @version 0.1 */ Class SudokuSolver{ /** * To store the input Sudoku * @access private * @var array $_input row == column mapping */ private $_input; /** * To store the currently solved sudoku at any moment of time * @access private * @var array $_currentSudoku row == column mapping */ private $_currentSudoku; /** * To store the probable values for each cell * @access private * @var array $_probable [row][col] == possible values array mapping */ private $_probable; /** * to store weather the sudoku have been solved or not * @access private * @var bool */ private $_solved = false; /** * store weather each cell is solved or not * @access private * @var array $_solvedParts row == column (bool) values */ private $_solvedParts = array ( array ( false, false, false, false, false, false, false, false, false ), array ( false, false, false, false, false, false, false, false, false ), array ( false, false, false, false, false, false, false, false, false ), array ( false, false, false, false, false, false, false, false, false ), array ( false, false, false, false, false, false, false, false, false ), array ( false, false, false, false, false, false, false, false, false ), array ( false, false, false, false, false, false, false, false, false ), array ( false, false, false, false, false, false, false, false, false ), array ( false, false, false, false, false, false, false, false, false ) ); /** * SudokuSolver constructor * * If the input sudoku is provided it will store to the {@link _input} property. * * @access public * @param array $input row == column mapping * @return void */ public function __construct($input = null){ // check if the input sudoku is provided, if yes then // store it in $_input if ( $input !== null ) $this -&gt; _input = $input; } /** * Input Method * * Explictly give a new input array if its not already provided in * the constructor. If already provieded in the constructore then * it will be replaced * * @access public * @param array $input row == column mapping * @return void */ public function input($input){ // store the received input into $_input $this -&gt; _input = $input; } /** * Solve Method * * The main function to start solving the sudoku and return the * solved sudoku * * @access public * @return array row == column mapping of solved sudoku */ public function solve (){ // Copy the input sudoku to _currentSudoku $this -&gt; _currentSudoku = $this -&gt; _input; // update _solvedParts of the given sudoku $this -&gt; _updateSolved (); // Start solving the sudoku $this -&gt; _solveSudoku(); // return the solved sudoku return $this -&gt; _currentSudoku; } /** * updateSolved Method * * Update the _solvedParts array to match the values of * _currentSudoku. * * @access private * @return void */ private function _updateSolved(){ // loop for rows for ($i = 0; $i &lt; 9; $i++ ) // loop for columns for ($j = 0; $j &lt; 9; $j++ ) // if the value exists for the corresponding row, column // then update the _solvedParts corresponding row, column // to true if ( $this -&gt; _currentSudoku[$i][$j] != 0 ) $this -&gt; _solvedParts[$i][$j] = true; } /** * _solveSudoku Method * * Main sudoku solving method * * @access private * @return void */ private function _solveSudoku(){ // continue running untill the sudoku is completly solved do{ // calculate the probable values for each cell an solve // available cells $this -&gt; _calculateProbabilityAndSolve(); // check weather the sudoku is completly solved $this -&gt; _checkAllSolved(); }while (!$this -&gt; _solved); // run till the _solved value becomes true } /** * _calculateProbabilityAndSolve Method * * Find the possible values for each cell and * solve it if possible * * @access private * @return void */ private function _calculateProbabilityAndSolve(){ // find possible values for each cell $this -&gt; _findPosibilites(); // check if each cell is solveable and if yes solve it $this -&gt; _solvePossible(); } /** * _findPosibilites Method * * Find possible values for each cell * * @access private * @return void */ private function _findPosibilites(){ // loop for rows for ($i = 0; $i &lt; 9; $i++ ){ // loop for columns for ($j = 0; $j &lt; 9; $j++ ){ // if the ixj cell is not solved yet if ( !$this -&gt; _solvedParts[$i][$j] ){ // find all possible values for cell ixj $this -&gt; _findAllProbables ($i, $j); } } } } /** * _solvePossible Method * * Solve possible cells using probable values calculated * * @access private * @return void */ private function _solvePossible(){ // loop for rows for ($i = 0; $i &lt; 9; $i++ ){ // loop for column for ($j = 0; $j &lt; 9; $j++ ){ // if cell ixj is not solved yet if ( !$this -&gt; _solvedParts[$i][$j] ){ // solve the cell ixj if possible using probable values // calculated $this -&gt; _solveIfSolveable ($i, $j); } } } } /** * _checkAllSolved Method * * check if all the cells have been solved * * @access private * @return void */ private function _checkAllSolved(){ // pre assign all solved as true $allSolved = true; // loop for rows for ($i = 0; $i &lt; 9; $i++ ){ // loop for columns for ($j = 0; $j &lt; 9; $j++ ){ // if allSolved is still true an the cell iXj is not if ( $allSolved and !$this -&gt; _solvedParts[$i][$j] ){ // set all solved as false $allSolved = false; } } } // copy the value of allSolved into _solved. $this -&gt; _solved = $allSolved; } /** * _solveIfSolveable Method * * Solve a single cell $rowx$col if it is solveable using * available probable datas * * @access private * @param int $row 0-8 * @param int $col 0-8 * @return bool */ private function _solveIfSolveable ($row, $col){ // if there is only one probable value for the cell $rowx$col if ( count ($this -&gt; _probable[$row][$col]) == 1 ){ // copy the only possible value to $value $value = $this -&gt; _probable[$row][$col][0]; // set the value of cell $rowx$col as $value an update solvedParts $this -&gt; _setValueForCell ($row, $col, $value); // return true as solved return true; } // pre assign $value as 0. ie; not solved $value = 0; // loop through all the possible values for $row x $col // and check if any possiblity can be extracted from it // by checking if its possible for the same number to be // positioned anywhere else thus confilicting with current // cell. If a possibility is not a possibility for any other // cell in the confilicting places then it is the value for // current cell foreach ($this -&gt; _probable[$row][$col] as $possible){ // a try-catch exception handling used here // as a control statement for continuing the main loop // if a value is possible in some place. try{ // loop through the current column for ($i = 0; $i &lt; 9; $i++ ){ // if the cell is solved continue the loop if ($this -&gt; _currentSudoku[$i][$col] != 0) continue; // if the possible is also possible in the $i x $col cell // then throw a ContinueException to continue the outer loop if (in_array($possible, $this -&gt; _probable[$i][$col])) throw new ContinueException ("Exists"); } // loop through the current row for ($i = 0; $i &lt; 9; $i++ ){ // if the cell is solved continue the loop if ($this -&gt; _currentSudoku[$row][$i] != 0) continue; // if the possible is also possible in the $i x $col cell // then throw a ContinueException to continue the outer loop if (in_array($possible, $this -&gt; _probable[$row][$i])) throw new ContinueException ("Exists"); } // find the start of the 3x3 grid with $row x $col cell $gridRowStart = $this -&gt; _findGridStart($row); $gridColStart = $this -&gt; _findGridStart($col); // loop row through the current 3x3 grid for ($i = $gridRowStart; $i &lt; $gridRowStart + 3; $i++){ // loop column through the current 3x3 gri for ($j = $gridColStart; $j &lt; $gridColStart + 3; $j++){ // if its the current $row x $col cell then // continue the loop if ($i == $row &amp;&amp; $j == $col ) continue; // if the cell is already solved then // continue the loop if ($this -&gt; _currentSudoku[$row][$i] != 0) continue; // if the possible is also possible in the // $i x $j cell then throw a ContinueException // to continue the outer loop if (in_array($possible, $this -&gt; _probable[$i][$j])) throw new ContinueException ("Exists"); } } // if the loop is not continued yet, // then that means this possible value is // not possible in any other conflicting // cells. So assign the value of $value to // $possible and break the loop. $value = $possible; break; }catch (ContinueException $e){ // if a ContinueException is thrown then contine // the outer loop continue; } } // if the value of $value is not 0 then the value of // the cell is $value. if ($value != 0){ // set the value of cell $rowx$col as $value an update solvedParts $this -&gt; _setValueForCell ($row, $col, $value); // return true as solved return true; } // return false as not solved yet. return false; } /** * _setValueForCell Method * * If a cell is solved then update the value for * that cell, and also update the {@link _solvedParts}. * * @access private * @param int $row 0-8 * @param int $col 0-8 * @param int $value 1-9 * @return void */ private function _setValueForCell($row, $col, $value){ // update the solved parts in _currentSudoku. $this -&gt; _currentSudoku[$row][$col] = $value; // update the corresponding _solvedParts. $this -&gt; _solvedParts[$row][$col] = true; } /** * _findAllProbables Method * * Find all possible values for any given cell using * other already solved or given cell values. * * @access private * @param int $row 0-8 * @param int $col 0-8 * @return void */ private function _findAllProbables ($row, $col){ // initially set the $probable as array 1 to 9. $probable = range(1,9); // loop through current column for ($i = 0; $i &lt; 9; $i++ ) // if the cell $i x $col is solved and the value of // cell $ix$col is in the $probable array then remove // that element. if ( ( $current = $this -&gt; _currentSudoku[$i][$col] ) != 0 and ( $key = array_search($current, $probable) ) !== false ) unset ($probable[$key]); // loop through the current row for ($i = 0; $i &lt; 9; $i++ ) // if the cell $row x $i is solved and the value of // cell $rowx$i is in the $probable array then remove // that element. if ( ( $current = $this -&gt; _currentSudoku[$row][$i] ) != 0 and ( $key = array_search($current, $probable) ) !== false ) unset ($probable[$key]); // find the start of the 3x3 grid with $row x $col cell $gridRowStart = $this -&gt; _findGridStart($row); $gridColStart = $this -&gt; _findGridStart($col); // loop row through the current 3x3 grid for ($i = $gridRowStart; $i &lt; $gridRowStart + 3; $i++) // loop column through the current 3x3 grid for ($j = $gridColStart; $j &lt; $gridColStart + 3; $j++) // if the cell $i x $j is solved and the value of // cell $ix$j is in the $probable array then remove // that element. if ( ( $current = $this -&gt; _currentSudoku[$i][$j] ) != 0 and ( $key = array_search($current, $probable) ) !== false ) unset ($probable[$key]); // Store the rest of the probable values to // _probable[$row][$col] $this -&gt; _probable[$row][$col] = array_values($probable); } /** * _findGridStart Method * * Find the start of the 3x3 grid in which the value * comes * * @access private * @param int $value 0-9 * @return int */ private function _findGridStart ($value){ // return the start of the current 3x3 grid return floor( $value / 3 ) * 3; } } /** * &lt;i&gt;ContinueException&lt;/i&gt; class * * Extends Exception. Used to throw exception for * continue the outer most loop. * */ Class ContinueException extends Exception{} ?&gt; </code></pre>

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<p>In the absence of a full-fledged tutorial, I am teaching myself to program in the <a href="http://factorcode.org/">Factor</a> language by writing a bunch of functions that I will eventually use in command-line scripts.</p> <p>One common operation I like to perform is to change the case of names of files contained in a given directory to uppercase or lowercase. I wrote the following code to perform this operation in Factor:</p> <pre><code>USING: fry kernel io.directories sequences unicode.case ; IN: util.directories : move-each-directory-file&gt;lower ( pathname -- ) [ dup &gt;lower ] move-each-directory-file ; : move-each-directory-file&gt;upper ( pathname -- ) [ dup &gt;upper ] move-each-directory-file ; : each-directory-file ( pathname quot -- ) '[ [ @ ] each ] with-directory-files ; inline : move-each-directory-file ( pathname quot -- ) '[ @ move-file ] each-directory-file ; inline </code></pre> <p>I have tried to factor as much code as possible into a reusable vocabulary. I look forward to suggestions for improvement.</p>

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<p>After reading an article on Skull Security mentioning the potential weakness of php's mt_rand function because of weak auto-seeding (<a href="http://ow.ly/4nrne" rel="nofollow">http://ow.ly/4nrne</a>), I decided to see what -- if any -- entropy I could find available from within php. The idea is to have enough (weak) sources that even if one or two are manipulated, lost or recovered, there's enough left to thwart brute force against the resulting passwords later.</p> <p>Hopefully the result is both readable and usable, although I don't expect it to be production-quality.</p> <pre><code>&lt;?php /** * Return a random password. * * v1.01 * Jumps through many hoops to attempt to overcome autoseed weakness of php's mt_rand function * */ function myRandomPassword() { // Change this for each installation $localsecret = 'qTgppE9T2c'; // Determine length of generated password $pwlength = 10; // Character set for password $pwchars = 'ABCDEFGHJKLMNPQRSTUVWXYZabcdefghjkmnpqrstuvwxyz0123456789'; $l = strlen( $pwchars ) - 1; // Get a little bit of entropy from sources that should be inaccessible to outsiders and non-static $dat = getrusage(); // gather some information from the running system $datline = md5(implode($dat)); // wash using md5 -- it's fast and there's not enough entropy to warrant longer hash $hardToGuess = $datline; $self = __FILE__; // a file the script should have read access to (itself) $stat = stat($self); // information about file such as inode, accessed time, uid, guid $statline = md5(implode($stat)); // wash $hardToGuess .= $statline; $preseed = md5(microtime()) . getmypid() . $hardToGuess . memory_get_usage() . disk_free_space('.') . $localsecret; $seed = sha1( $preseed ); // final wash, longer hash // Seed the mt_rand() function with a better seed than the standard one mt_srand ($seed); // Pick characters from the lineup, using the seeded mt_rand function $pw = ''; for ( $i = 0; $i &lt; $pwlength; $i++ ) { $pw .= $pwchars{ mt_rand( 0, $l ) }; } // Return the result return $pw; } echo myRandomPassword(); ?&gt; </code></pre> <p>Revision 1.01 adds a local secret.</p>

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<p>I'm making a scripting language parser and it's shaping up well but it takes about 30ms to do 30 or so odd/even checks.</p> <p><code>Profiler</code> tells me that it's taking most of the time in the <code>InvokeOperator.Operate</code> function but that doesn't tell me a lot because the Operate call the Run method on the <code>CodeBlock</code> which in turn again calls the Operate call and makes it very hard to actually determine what's taking as long.</p> <p>Here's the <a href="https://github.com/LukaHorvat/Kento" rel="nofollow">Github repo</a></p> <p>Here are the most important bits of the code:</p> <pre><code>Stack&lt;Token&gt; solvingStack = new Stack&lt;Token&gt;(); for ( int i = 0 ; i &lt; value.Count ; ++i ) { if ( value[ i ] is Operator ) { Operator op = (Operator)value[ i ]; if ( op.Type == OperatorType.PrefixUnary || op.Type == OperatorType.SufixUnary ) { op.Operate( ( solvingStack.Pop() as Value ), new NoValue() ); } else { Value second = (Value)solvingStack.Pop(); Value result = op.Operate( ( solvingStack.Pop() as Value ), second ); solvingStack.Push( result ); } } else { solvingStack.Push( value[ i ] ); } } Compiler.ExitScope(); if ( solvingStack.Count == 0 ) return new NoValue(); else return (Value)solvingStack.Peek(); </code></pre> <p>It's how the code is parsed after the infix expression is turned into RPN. A token can be an operator or a value and a value can be a literal, identifier, <code>codeblock</code>.</p> <p>A somewhat special case is a function because it's not parsed to RPN directly but only the code inside of it is. Then is there's an invoke operator, it takes the array of arguments that was provided and the function before it and runs the function (which inherits from <code>CodeBlock</code>, so it also runs the same thing that is shown here).</p> <p>What each operator does on different types of values is determined by the operator itself in the Operators.cs file.</p>

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<p>I have the following code for reading <a href="http://htk.eng.cam.ac.uk/" rel="nofollow">HTK</a> feature files. The code below is working completely correct (verified it with unit tests and the output of the original HTK toolkit).</p> <pre><code>from HTK_model import FLOAT_TYPE from numpy import array from struct import unpack def feature_reader(file_name): with open(file_name, 'rb') as in_f: #There are four standard headers. Sample period is not used num_samples = unpack('&gt;i', in_f.read(4))[0] sample_period = unpack('&gt;i', in_f.read(4))[0] sample_size = unpack('&gt;h', in_f.read(2))[0] param_kind = unpack('&gt;h', in_f.read(2))[0] compressed = bool(param_kind &amp; 02000) #If compression is used, two matrices are defined. In that case the values are shorts, and the real values are: # (x+B)/A A = B = 0 if compressed: A = array([unpack('&gt;f',in_f.read(4))[0] for _ in xrange(sample_size/2)], dtype=FLOAT_TYPE) B = array([unpack('&gt;f',in_f.read(4))[0] for _ in xrange(sample_size/2)], dtype=FLOAT_TYPE) #The first 4 samples were the matrices num_samples -= 4 for _ in xrange(0,num_samples): if compressed: yield ((array( unpack('&gt;' + ('h' * (sample_size//2)),in_f.read(sample_size)) ,dtype=FLOAT_TYPE) + B) / A) else: yield (array( unpack('&gt;' + ('f' * (sample_size//4)),in_f.read(sample_size)), dtype=FLOAT_TYPE)) </code></pre> <p>How can I speed up this code, are there things I should improve in the code?</p>

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<p>I have an extension that implements all the BinaryReader/BinaryWriter in the Stream class. I want to create generic methods for them. Is there a nicer way of doing this?</p> <pre><code>public static void Write&lt;T&gt;(this Stream stream, T num) { if (num is byte) { stream.Write((byte)(object)num); } else if (num is Int16) { stream.Write((Int16)(object)num); } else if (num is Int32) { stream.Write((Int32)(object)num); } } public static T Read&lt;T&gt;(this Stream stream) { object ret = null; if (typeof(T) == typeof(byte)) ret = stream.ReadInt8(); else if (typeof(T) == typeof(Int16)) ret = stream.ReadInt16(); else if (typeof(T) == typeof(Int32)) ret = stream.ReadInt32(); if (ret == null) throw new ArgumentException("Unable to read type - " + typeof(T)); return (T)ret; } </code></pre> <p>Now using this for the Read method.</p> <pre><code>static Dictionary&lt;Type, Func&lt;Stream, object&gt;&gt; ReadFuncs = new Dictionary&lt;Type, Func&lt;Stream, object&gt;&gt;() { {typeof(bool), s =&gt; s.ReadBoolean()}, {typeof(byte), s =&gt; s.ReadInt8()}, {typeof(Int16), s =&gt; s.ReadInt16()}, {typeof(Int32), s =&gt; s.ReadInt32()}, {typeof(Int64), s =&gt; s.ReadInt64()}, {typeof(string), s =&gt; s.ReadString()}, }; public static T Read&lt;T&gt;(this Stream stream) { if (ReadFuncs.ContainsKey(typeof(T))) return (T)ReadFuncs[typeof(T)](stream); throw new NotImplementedException(); } </code></pre>

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<p>I have the following code which uses four if statements to check the value in four different combo boxes. </p> <pre><code>if (!String.IsNullOrEmpty(tx_cmb_Circuits1.Text.Trim())) emp.CircuitEmail_Group_Rels.Add( new Circuit_Email_Group_Rel { Circuits = (Circuits) tx_cmb_Circuits1.SelectedItem, Group = emp }); if (!String.IsNullOrEmpty(tx_cmb_Circuits2.Text.Trim())) emp.CircuitEmail_Group_Rels.Add( new Circuit_Email_Group_Rel { Circuits = (Circuits) tx_cmb_Circuits2.SelectedItem, Group = emp }); if (!String.IsNullOrEmpty(tx_cmb_Circuits3.Text.Trim())) emp.CircuitEmail_Group_Rels.Add( new Circuit_Email_Group_Rel { Circuits = (Circuits) tx_cmb_Circuits3.SelectedItem, Group = emp }); if (!String.IsNullOrEmpty(tx_cmb_Circuits4.Text.Trim())) emp.CircuitEmail_Group_Rels.Add( new Circuit_Email_Group_Rel { Circuits = (Circuits) tx_cmb_Circuits4.SelectedItem, Group = emp }); </code></pre> <p>Is there are shorter way to do the same. Please review my code.</p>

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<p>I have been trying to learn more about using bits/bitfields/bitmask or whatever you call them exactly in PHP for different settings and permissions. With the help of others, I have come up with this class. It has come a long way from when I started it but I am looking for any ideas on how to improve it more.</p> <pre><code>&lt;?php abstract class BitField { private $value; public function __construct($value=0) { $this-&gt;value = $value; } public function getValue() { return $this-&gt;value; } public function get($n) { if (is_int($n)) { return ($this-&gt;value &amp; (1 &lt;&lt; $n)) != 0; }else{ return 0; } } public function set($n, $new=true) { $this-&gt;value = ($this-&gt;value &amp; ~(1 &lt;&lt; $n)) | ($new &lt;&lt; $n); } public function clear($n) { $this-&gt;set($n, false); } } class UserPermissions_BitField extends BitField { const PERM_READ = 0; const PERM_WRITE = 1; const PERM_ADMIN = 2; const PERM_ADMIN2 = 3; const PERM_ADMIN3 = 4; } class UserPrivacySettings_BitField extends BitField { const PRIVACY_TOTAL = 0; const PRIVACY_EMAIL = 1; const PRIVACY_NAME = 2; const PRIVACY_ADDRESS = 3; const PRIVACY_PHONE = 4; } ?&gt; </code></pre> <p>Example usage: </p> <pre><code>&lt;?php $user_permissions = 0; //This value will come from MySQL or Sessions $bf = new UserPermissions_BitField($user_permissions); // turn these permission to on/true $bf-&gt;set($bf::PERM_READ); $bf-&gt;set($bf::PERM_WRITE); $bf-&gt;set($bf::PERM_ADMIN); $bf-&gt;set($bf::PERM_ADMIN2); $bf-&gt;set($bf::PERM_ADMIN3); //turn permission PERM_ADMIN2 to off/false $bf-&gt;clear($bf::PERM_ADMIN2); // sets $bf::PERM_ADMIN2 bit to false // check if permission PERM_READ is on/true if ($bf-&gt;get($bf::PERM_READ)) { // can read echo 'can read is ON&lt;br&gt;'; } if ($bf-&gt;get($bf::PERM_WRITE)) { // can write echo 'can write is ON&lt;br&gt;'; } if ($bf-&gt;get($bf::PERM_ADMIN)) { // is admin echo 'admin is ON&lt;br&gt;'; } if ($bf-&gt;get($bf::PERM_ADMIN2)) { // is admin 2 echo 'admin 2 is ON&lt;br&gt;'; } if ($bf-&gt;get($bf::PERM_ADMIN3)) { // is admin 3 echo 'admin 3 is ON&lt;br&gt;'; } ?&gt; </code></pre>

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<blockquote> <p>Given an array that is first sorted non-decreasing and then rotated right by an unspecified number of times, find the index of its minimal element efficiently. If multiple such minimal elements exist, return the index of any one.</p> <p>Idea: Conceptually, divide the array into two parts: the "larger" subpart (to the left) which consists of large numbers brought here from the extreme right by rotation, and the "smaller" subpart which starts with the smallest element. We can always tell in which part we are, and move left/right accordingly.</p> </blockquote> <p>Notes: When the array has multiple minimal elements, the index of the leftmost one in the "right" subpart is returned.</p> <pre><code>int getMinimIndex (const int *const a, size_t left, size_t right) { assert(left&lt;= right); // Special cases: // 1 If left &amp; right are same , return if (left ==right) return left; // 2 For an array of size 2, return the index of minimal element if (left == right - 1) return a[left]&lt;=a[right]?left:right; // 3 If the array wasn't rotated at all, if (a[left] &lt; a[right]) return left; // General case // Go to the middle of the array size_t mid = (left + right) &gt;&gt; 1; // If we stepped into the "larger" subarray, we came too far, // hence search the right subpart if (a[left] &lt;= a[mid] ) return getMinimIndex(a, mid, right); else // We're still in the "smaller" subarray, hence search left subpart return getMinimIndex(a,left, mid); } </code></pre> <p><strong>Unit tests:</strong></p> <pre><code>\#define lastIndex(a) ((sizeof(a)/sizeof(a[0]))-1) int main() { int a1[] = {7,8,9,10,11,3}; int a2[] = {1}; int a3[] = {2,3,1}; int a4[] = {2,1}; int a5[] = {2,2,2,2,2}; int a6[] = {6,7,7,7,8,8,6,6,6}; int a7[] = {1,2,3,4}; printf("\n%d", getMinimIndex(a1,0, lastIndex(a1))); // 5 printf("\n%d", getMinimIndex(a2,0, lastIndex(a2))); // 0 printf("\n%d", getMinimIndex(a3,0, lastIndex(a3))); // 2 printf("\n%d", getMinimIndex(a4,0, lastIndex(a4))); // 1 printf("\n%d", getMinimIndex(a5,0, lastIndex(a5))); // 3 printf("\n%d", getMinimIndex(a6,0, lastIndex(a6))); // 6 printf("\n%d", getMinimIndex(a7,0, lastIndex(a7))); // 0 return 0; } </code></pre>

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<p>Using the property that GCD(a, b) = GCD(b, r) where r is the remainder when you compute (a / b), you can write a recursive function as follows:</p> <pre><code>(define (gcd a b) ; recursive (if (= 0 b) a (gcd b (remainder a b)))) </code></pre> <p>I also tried to write the following as an iterative function, but it still looks very similar to the recursive solution to my eye. Is this a correct, iterative solution?</p> <pre><code>(define (i-gcd a b) ; is this iterative? (i-gcd-iter (remainder a b) b)) (define (i-gcd-iter acc b) (if (= 0 b) acc (gcd b (remainder acc b)))) </code></pre> <p>EDIT: It appears that the first solution was actually iterative, and in fact very similar to the solution written in SICP (http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-11.html). What would a recursive solution to this problem look like?</p>

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