app.py

import streamlit as st 

st.title('Welcome to BMI Calculator')

weight = st.number_input('Enter your weight in Kgs')
status = st.radio('select your height format:',('cms','meters','feet'))

try:
    if status == 'cms':
        height = st.number_input('Centimeters')
        bmi = weight/((height/100)**2)

    elif status == 'meters':
        height = st.number_input('meters')
        bmi = weight/((height)**2)

    elif status == 'feet':
        height = st.number_input('feet')
        bmi = weight/((height/3.28)**2)    
except:
    print('Zero Division Error')

if (st.button('Calculate BMI')):
    st.write('Your BMI index is {}.'.format(round(bmi)))
    if (bmi<16):
        st.error('You are extremely underweight')
    elif (bmi>=16 and bmi<18.5):
        st.warning('You are Underweight')
    elif (bmi>18.5 and bmi <25):
        st.success('Healthy')
    elif (bmi>25 and bmi<30):
        st.warning('Overweight')
    elif (bmi>=30):
        st.error('Extremely overweight')
    st.balloons()