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 extremly underweight')
   elif (bmi>=16) and (bmi<18.5):
      st.warning('You are underweight')
   elif (bmi>=18.5) and (bmi<23):
      st.success('You are Healthy')
   elif (bmi>=23) and (bmi<30):
      st.warning('You are overweight')
   elif (bmi>30):
      st.error('You are extremly overweight')