#一、简易版用户登录，此程序直到用户输入正确的用户名和密码，不然不会退出
1 _name = "liangchen"
2 _passwd = "abc123"
3 while True:
4 username = input("username:")
5 password = input("password:")
6 if username == _name and password == _passwd:
7 print("welcome %s login"%_name)
8 break
9 else:
10 print("Invalid username or password!")
#二、简易版用户登录，用户输入正确的用户名和密码或者用户输入三次错误都会退出登录
_name = "liangchen"
_passwd = "abc123"
login_time = 0
while login_time<3:
username = input("username:")
password = input("password:")
if username == _name and password == _passwd:
print("welcome %s login"%_name)
break
else:
print("Invalid username or password!")
login_time += 1
if(login_time == 3):
print("输入次数过多，退出登录！")
break
