auto save

diy2.py

@@ -6,5 +6,10 @@ while True:
     if name == username and password == userpassword:
         print("登录成功!")
         break
-    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")
+        continue
+    if password!=userpassword:
+        print("用户密码错误，请重新输入")
+    
 print("欢迎来到贝尔编程!")
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