(1) . 登錄成功后，用戶選擇幸運抽獎菜單，進入幸運抽獎功能
(2) . 輸入會員卡號，系統(tǒng)生成5個4位隨機數(shù)作為幸運數(shù)字
(3) . 如果會員卡號是其中之一，則成為本日幸運會員；否則不是幸運會員

static void Main(string[] args)
    {
        int max = 99999;
        int min = 1000;
        Random rd = new Random();
        rd.Next(min, max);
        int a = 0;
        int id =0;
        string user = "";
        string key = "";
        string b = "";
        Console.WriteLine("*****歡迎進入獎客富翁系統(tǒng)*****");
        Console.WriteLine("           1.注冊");
        Console.WriteLine("           2.登錄");
        Console.WriteLine("           3.抽獎");
        Console.WriteLine("******************************");
        Console.WriteLine("請選擇菜單：");
        a = Convert.ToInt32(Console.ReadLine());
        switch (a)
        {
            case 1:
                Console.WriteLine("[獎客富翁系統(tǒng)>注冊]");
                Console.WriteLine("請?zhí)顚懹脩糇孕畔?");
                Console.WriteLine("用戶名:");
                user = Console.ReadLine();
                Console.WriteLine("密碼:");
                key = Console.ReadLine();
                Console.WriteLine("注冊成功，請記好你的會員卡號");
                Console.WriteLine("用戶名\t\t密碼\t\t會員卡號");
                Console.WriteLine("{0}\t\t{1}\t\t{2}", user, key, rd.Next(min, max));
                Console.WriteLine("繼續(xù)嗎?(y/n)");
                b = Console.ReadLine();
                break;
            case 2:
                Console.WriteLine("[獎客富翁系統(tǒng)>登錄]");
                Console.WriteLine("請輸入用戶名:");
                user = "admin";
                key ="123456";
                string yonghu =Console.ReadLine();
                Console.WriteLine("請輸入密碼:");
                string mima =Console.ReadLine();
                for (int i = 0; i < 4; i++)
                {
                    if (user == yonghu & key == mima)
                    {
                        Console.WriteLine("歡迎您:{0}", yonghu);
                        break;
                    }
                    else
                    {
                        Console.WriteLine("你還剩{0}次機會", 3 - i);
                        continue;
                    }
                }
                break;
            case 3:
                Console.WriteLine("[獎客富翁系統(tǒng)>抽獎]");
                Console.WriteLine("請輸入你的卡號");
                id =Convert.ToInt32(Console.ReadLine());
                Console.WriteLine("今日的幸運數(shù)字為：");
                for(int i =0;i<4;i++)
                {
                    Console.WriteLine(rd.Next(min, max));
                }
                if (rd.Next(min, max) == id)
                {
                    Console.WriteLine("恭喜！你是本日的幸運會員!");
                }
                else
                {
                    Console.WriteLine("抱歉！您不是本日的幸運會員！");
                }
                break;
        }
        Console.WriteLine("繼續(xù)嗎？（y/n）");
        b = Console.ReadLine(); switch (b)
        {
            case "n":
                Console.WriteLine("系統(tǒng)退出，謝謝使用");
                break;
            case "y":
                Console.WriteLine("");
                break;
        }
        Console.ReadKey();
    }