简单Struct+ArrayList选择买东西：购物车思路

namespace ConsoleApplication30
{
    class Program
    {
        struct buy
        {
            public string name;
            public double prc;
            public int shul;
        }
        static void Main(string[] args)
        {
            ArrayList al = new ArrayList();
            double sum = 0;
            while (true)
            {
                buy b = new buy();
                Console.Write("BANDAI官方旗舰店欢迎您！" + "\n" + "请输入您选择的商品：");
                b.name = Console.ReadLine();
                Console.Write("请输入你要商品的价格（/元）：");
                b.prc = Convert.ToDouble(Console.ReadLine());
                Console.Write("请输入你要商品的数量（/个）：");
                b.shul = Convert.ToInt32(Console.ReadLine());
                al.Add(b);//结构体b累计到集合中
                Console.Write("请问是否结账：Y/N：");
                string d = Console.ReadLine(); 
                if (d.ToUpper()=="Y")
                {
                    break;
                }
                else
                {

                }
            }
            for (int i = 0; i < al.Count; i++)
            {
                sum = sum + ((buy)al[i]).prc * ((buy)al[i]).shul;//累计花了多少钱
            }
            if (sum>=100&&sum<=200)
            {
                Console.WriteLine("您这次总共花销为"+sum+"\t折扣为9.5折\t实际花销为"+(sum*0.95)+"元\t节省了"+(sum*0.05)+"元");
            }
            else if (sum > 200 && sum <= 300)
            {
                Console.WriteLine("您这次总共花销为" + sum + "\t折扣为9折\t实际花销为" + (sum * 0.90) + "元\t节省了" + (sum * 0.1) + "元");
            }
            else if (sum >300 && sum <= 400)
            {
                Console.WriteLine("您这次总共花销为" + sum + "\t折扣为8.5折\t实际花销为" + (sum * 0.85) + "元\t节省了" + (sum * 0.15) + "元");
            }
            else if (sum>0&&sum<100)       
            {
                Console.WriteLine("您这次总共花销为" + sum + "\t无折");
            }
            else
            {
                Console.WriteLine("您这次总共花销为" + sum + "\t折扣为8折\t实际花销为" + (sum * 0.8) + "元\t节省了" + (sum * 0.2) + "元");
            }
            Console.ReadLine();
        }
    }
}