save project

diy.py

 username="python"
 userpassword="789456"
-name=input("请输入用户名：")
-password=input("请输入密码：")
-if username==name and userpassword==password:
-    print("登入成功")
+while True:
+    name=input("请输入用户名：")
+    password=input("请输入密码：")
+    if username==name and userpassword==password:
+        print("登入成功")
+        break
+    if username!=name:
+        print("用户名不存在，请重新输入")
+    if userpassword!=password:       
+        print("用户名和密码错误，请重新输入")
+print("欢迎来到")
\ No newline at end of file