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 username !=name:
+        print("重新输入用户名")
+    if userpassword !=password:
+        print("重新输入密码")
+
+print("欢迎来到贝尔编程!")