save project

diy4.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("登陆成功")
+        break
+    if name!=username:
+        print("用户名不存在请重新输入")
+        continue
+    if password!=userpassword:
+        print("密码不存在请重新输入")
+print("欢迎来到贝尔编程")
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