auto save

diy2.py

 username = "python"
 userpassword = "123456"
-while True: password == userpassword:
-    print('登录成功！')
+while True:
     name = input("请输入用户名:")
     password = input("请输入密码:")
-    if name == username and
-        
+    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!")
+    if password != userpassword:
+        print("密码输入错误")
 print("欢迎来到贝尔编程!")
+                                                       
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