save project

diy2.py

+
 username = "python"
 userpassword = "123456"
+i=3
 while True:
+    if i>0:
         nema = input("请输入用户名:")
         password = input("请输入密码:")
+        i-=1
         if nema == username and password == userpassword:
             print("登录成功!")
             break
-    elif nema!=username:
+        if nema!=username:
             print("用户名输入错误请重新输入")
-
-    else:
+            continue
+        if password!=userpassword
             print("密码输入戳无请重新输入")
+    else:
+        print("输入失败")
+        exit()
 print("欢迎来到贝尔编程!")
\ No newline at end of file