save project

4.py

+username="python"
+userpassword="123456"
+while True:
+    name=input("请输入账号：")
+    password=input("请输入密码：")
+    if username==name and userpassword==password:
+        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("密码输入有误，请重新输入")
+print("欢迎来到贝尔编程")
\ No newline at end of file