auto save

diy2.py

@@ -6,6 +6,10 @@ while True:
     if name == username and password == userpassword:
         print("登录成功!")
         break
-    if name != username or password != userpassword:
+    if name != username and password != userpassword:
         print("用户名和密码错误!请重新输入")
+    if name != username:
+        print("用户名不存在!请重新输入")
+    if password != userpassword:
+        print("密码错误!请重新输入") 
 print("欢迎来到贝尔编程!")
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