题目是：提示用户输入用户名。然后再提示输入密码，如果用户名是admin并且密码是888888则提示正确，否则错误。如果用户名不是admin还提示用户名不存在.
      Console.WriteLine("please input user name");
            string s2=Console.ReadLine();
            int user = Convert.ToInt32(s2);
            Console.WriteLine("please input password");
            string s1 = Console.ReadLine();
            int password = Convert.ToInt32(s1);
            if (password == 888888&&user ==admin)
            {
                Console.WriteLine("正确");
               
            }            
           else if(password!=888888)
            {
               Console.WriteLine("密码错误");
           }
            else(user!=admin);
            {
            Console.WriteLine(用户名不存在);
为什么这样写程序无法通过？