(1) . 輸入用戶名和密碼，系統(tǒng)產(chǎn)生4位隨機數(shù)作為卡號。
(2) . 注冊成功，顯示注冊信息并修改注冊標(biāo)識為true

static void Main(string[] args)
    {
        int max = 99999;
        int min = 1000;
        Random rd = new Random();
        rd.Next(min, max);
        int a = 0;
        string user ="";
        string key ="";
        string b = "";
        Console.WriteLine("*****歡迎進(jìn)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]");
                break;
            case 3:
                Console.WriteLine("[獎客富翁系統(tǒng)>抽獎]");
                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();
    }