以缩进符和冒号标志语块：

 

#!/usr/bin/python

#Filename: if.py

number = 23

running = True

while running:

    guess = int(input('Enter an integer : '))

    if guess == number:

        print('Congratulations,you guessed it.')         print('(but you do not win any prizes!)')         running = False     elif guess < number:         print('No,it is a little higher than that')     else:         print('No,it is a little lower than that') else:     print('the while loop is over.')