//简单工厂,根据输入的参数,返回一个父类对象。父类对象中装的是子类对象。
        //参数:优惠的选项
        //返回值:打折类的父类
        public CalFather CalMoney(string input)
        {
            CalFather cal = null;

            switch (input)
            {
            case "1": cal = new CalNormal();
                break;

            case "2": cal = new CalRate(0.9);
                break;

            case "3": cal = new CalRate(0.85);
                break;

            case "4": cal = new CalMN(300, 50);
                break;

            case "5": cal = new CalMN(500, 100);
                break;

            default:
                break;
            }

            return(cal);
        }
        public void AskBuying()
        {
            Console.WriteLine("请问您要买什么吗?");
            Console.WriteLine("我们这里有Acer,Samsung,Banana,JiangYou");
            string strType = Console.ReadLine();

            Console.WriteLine("需要多少?");
            int count = Convert.ToInt32(Console.ReadLine());

            //去仓库取货
            ProductFather[] pros = ck.QuHuo(strType, count);
            //计算货物的价钱
            double realMoney = GetMoney(pros);

            Console.WriteLine("你实际应付{0}", realMoney);
            //打折信息
            Console.WriteLine("优惠促销1、不打折;2、打九折;3、打八五折;4、买300送50;5、买500送100");
            string    input = Console.ReadLine();
            CalFather cal   = CalMoney(input);

            Console.WriteLine("实际应付{0}元", cal.GetPayMoney(realMoney));
            //给出小票的信息
            Console.WriteLine("以下是您的购物信息");
            foreach (var item in pros)
            {
                Console.WriteLine("货物名称:{0},货物单价:{1},货物编号:{2}", item.Name, item.Price, item.ID);
            }
        }