day05_06 continue语句、while循环

输入满3次跳出,然后留一句话

for i in range(3):
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." %_user)
        passed_authentication = True
        break
    else:
        print("Invalid username or password")

if not passed_authentication :
    print("您的输出次数已经满3次,拜拜")

　　方法二

for i in range(3):
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." %_user)
        break
    else:
        print("Invalid username or password")

if i == 2 :
    print("您的输出次数已经满3次,拜拜")

　　方法三

for i in range(3):
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." %_user)
        break
    else:
        print("Invalid username or password")

if i == 2 :
    print("您的输出次数已经满3次,拜拜")

　　只要上面的for循环正常执行完毕,中间没有被打断(break),就会执行else语句,break过后,就不会执行后面的else语句

这个用法python特有

while死循环

while True:
    print("dang")

　　

_user = "alex"
_passwd = "abc123"

counter = 0
while counter < 3 :
    username = input("请输入您的姓名:")
    password = input("请输入您的密码:")
    if username == _user and password == _passwd :
        print("welcome %s login..." %_user)
        break
    else:
        print("您输入的账号或者密码错误,请重新输入")
    counter += 1
else:
    print("请的输入次数已满3次,拜拜啦")

　　

while之后也可以加上else

如果想测试程序,可以使用debug测试

输入三次后让用户选择是否需要继续玩?

_user = "alex"
_passwd = "abc123"

counter = 0
while counter < 3 :
    username = input("请输入您的姓名:")
    password = input("请输入您的密码:")
    if username == _user and password == _passwd :
        print("welcome %s login..." %_user)
        break
    else:
        print("您输入的账号或者密码错误,请重新输入")
    counter += 1

    if counter == 3:
        keep_going_choice = input("还想玩买?y/n")
        if keep_going_choice == 'y':
            counter = 0
else:
    print("请的输入次数已满3次,拜拜啦")