context1: Automatically and dynamically allocated objects are only initialized if an initial value is explicitly specified; otherwise they initially have indeterminate values (typically, whatever bit pattern <strong>happens</strong> to be present in the storage, which might not even represent a valid value for that type). If the program attempts to access an uninitialized value, the results are undefined. Many modern compilers try to detect and warn about this problem, but both false positives and false negatives <strong>occur</strong>.
context2: Most turns contain some degree of pitch or slice. During a turn in an oblique plane, a pitch turn <strong>occurs</strong> when the aircraft's nose points above the horizon, causing an increase in altitude. A slice turn <strong>happens</strong> when the nose points below the horizon, causing a decrease in altitude.