auto save

diy2.py

-username = "python"
-userpassword = "123456"
-while True:
-    name = input("请输入用户名:")
-    password = input("请输入密码:")
-    if name == username and password == userpassword:
-        print("登录成功!")
-        break
-    if name != username:
-        print("用户名不存在，请从新输入：")
-    elif password != userpassword:
-        print("密码输入错误，请从新输入：")
-print("欢迎来到贝尔编程!")
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