wheil循环 for循环

wheil循环 登录密码用户只能输入3次

counter = 0 "定义开始次数"
_user = "wl"
_password = "aaa123"

while counter <3:

username = input("Username:")
password = input("password:")

if username == _user and password == _password:

print("wel come %s login" % _user)

break # 跳出 中断
else:
print("输入错误")
counter += 1
else:
print("超过3次输入")

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用户输入3次错误可以按Y继续

counter = 0
_user = "wl"
_password = "aaa123"
while counter <3:
username = input("Username:")
password = input("password:")
if username == _user and password == _password:
print("wel come %s login" % _user)
break # 跳出 中断
else:
print("输入错误")
counter += 1
if counter ==3:
keep = input("继续请按Y")
if keep == "y":
counter=0
else:
print("超过3次输入")

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布尔运算

# (True) and (False) and 左右两边执行结果都是True 才为True真

# (True) or (False) or左右两边执行结果任意结果是True真 就为真

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age= 50

flag= True

while flag:
user_input_age = int(input("请输入年龄："))
if user_input_age == age:
print("输入正确")

elif user_input_age> age:
print("输入年龄过大")

else:
print("你输入年龄小于")

print("111")

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