死循环

#/usr/bin/env python
input_number=19
while True:                                           #==>无限循环
    number=int(input("please input your number:"))  #==>注意python3.0默认输入的是字符串，需要int转换
    if number == input_number:
        print("the number you put is true")
        break                                         #==>条件满足时结束循环
    elif number > input_number:
        print("the number you put is big")
    else:
        print("the number you put is small")

循环控制