要求：根據(jù)要求寫代碼

代碼：

namespace 任務1
{
class Program
{

    static void Main(string[] args)
    {
        string flag ="";   //用于標識用戶是否繼續(xù)

        string userName = "";   //用戶名
        string password = "";   //密碼
        string cardNum = "";    //會員卡號

        bool isReg = false;
        bool isLogin = false;

        //獲得隨機數(shù)
        Random rd = new Random();
        int max = 9999;
        int min = 1000;


        do{
            Console.WriteLine(@"
*************歡迎進入魔法師幸運抽獎系統(tǒng)*************
                1锋边、注冊
                2揍鸟、登錄
                3运杭、抽獎
*************************************************
");
            Console.Write("請選擇菜單:");
            string str_menu_num = Console.ReadLine();
            switch (str_menu_num)
            {
                case "1":
                    Console.WriteLine("魔法師幸運抽獎系統(tǒng) > 注冊");
                    string [] result = Reg();
                    if (string.IsNullOrEmpty(result[0]))
                    {
                        isReg = false;
                       
                    }
                    else
                    {
                        userName = result[0];
                        password = result[1];
                        cardNum = result[2];
                        isReg = true;
                    }

                    break;
                case "2":
                    if (isReg)
                    {
                        Console.WriteLine("魔法師幸運抽獎系統(tǒng) > 登錄");
                        for (int i = 1; i <= 3; i++)
                        {
                            Console.Write("第{0}/3次,請輸入用戶名：",i);
                            string un = Console.ReadLine();
                            Console.Write("第{0}/3次患久，請輸入密碼:",i);
                            string pw = Console.ReadLine();
                            if (userName == un && password == pw)
                            {
                                Console.WriteLine("歡迎您:{0}", userName);
                                isLogin = true;
                                break;
                            }
                            else
                            {
                                isLogin = false;
                                continue;
                            }
                        }
                        
                    }
                    else
                    {
                        Console.WriteLine("您沒有注冊，請先注冊后再登錄");
                    }

                    
                    break;
                case "3":
                   
                    if (isLogin)
                    {
                        Console.WriteLine("魔法師幸運抽獎系統(tǒng) > 抽獎");
                        Console.Write("請輸入會員卡號:");
                        string str_card_num = Console.ReadLine();
                        string[] lucknums = new string[5];
                        Console.Write("本日的幸運數(shù)字為:");
                        for (int i = 0; i < lucknums.Length; i++)
                        {
                            lucknums[i] = rd.Next(min, max).ToString();
                            Console.Write(lucknums[i] + "\t");
                        }
                        int index = Array.IndexOf(lucknums, str_card_num);
                        if (index == -1)
                        {
                            Console.WriteLine("抱歉忠荞，您不是本日的幸運會員");
                        }
                        else
                        {
                            Console.WriteLine("恭喜您多搀，您中獎了了~~~");
                        }
                    }
                    else
                    {
                        Console.WriteLine("您沒有登錄，請先登錄后再抽獎");
                    }


                    break;
                default:
                    Console.WriteLine("您的輸入有誤~");
                    break;
            }

            Console.Write("繼續(xù)嗎侧甫？(y/n)");
            flag = Console.ReadLine();
        }while(flag == "y"||flag == "Y");

        Console.WriteLine("系統(tǒng)退出珊佣，謝謝使用");


        Console.ReadKey();
    }

    /**
     * 注冊
     * */
    static string[] Reg()
    {
        string[] ret = new string[3];

        Random rd = new Random();
        int max = 9999;
        int min = 1000;

        Console.WriteLine("請?zhí)顚憘€人注冊信息");
        Console.Write("用戶名:");
        string userName = Console.ReadLine();//獲得用戶輸入的用戶名
        
        if (userName == "admin")
        {
            Console.WriteLine("admin帳戶已被占用");
            return ret;
        }
        
        //Console.WriteLine();
        Console.Write("密碼:");
       string password = Console.ReadLine();  //獲得用戶輸入的密碼
        //用隨機的數(shù)作為卡號
       string cardNum = rd.Next(min, max).ToString();
        Console.WriteLine("注冊成功，請記好您的會員卡號");
        Console.WriteLine("用戶名\t密碼\t會員卡號");
        Console.WriteLine("{0}\t{1}\t{2}", userName, password, cardNum);

        ret[0] = userName;
        ret[1] = password;
        ret[2] = cardNum;

        return ret;

    }
}

}