1、死循环学会用法

a = 1while True:    print(a)    a +=1

2、无限次输入，直到输对，才退出

_age = 18while True:    guess_age = int(input("guess_age:"))    if guess_age == _age:        print("Good!!!!")        break    else:        print("no,please input")

3、限制输入三次，超过三次，提示输入次数太多退出

_age = 18count = 0while count<3:    guess_age = int(input("guess_age:"))    if guess_age == _age:        print("Good!!!!")        break    elif guess_age > _age:        print("no,cai da le ...")    else:        print("no,cai xiao le ...")    count +=1else:    print("you have tried too many times...quit")