auto save

diy2.py

@@ -6,5 +6,8 @@ while True:
     if name == username and password == userpassword:
         print("登录成功!")
         break
+    if name != username:
+        print("用户名不存在，请重新输入！")
+    if password != userpassword:
     print("用户名和密码错误!请重新输入")
 print("欢迎来到贝尔编程")
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