Python 练习: 简单的用户登录判断

_user = "klvchen"
_passwd = "123456"
counter = 0

while counter < 3:
    username = raw_input("Username: ")
    password = raw_input("Password: ")

    if username == _user and password == _passwd :
        exit("welcome %s login!" % _user)
    else:
        print("Invalid username or password!")

    counter += 1
    if counter == 3:
        tmp = raw_input("Do you want to try again[Y/n]")
        if tmp == "Y":
            counter = 0

 注意：

exit()里面可以跟字符串

if 判断表达式可以跟 and ，or