求助购买数量在统计的时候值为什么不改变

Question

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;namespace Test5
{
    class Program
    {
       static void Main(string[] args)
        {
            Shopping myShopping = new Shopping();
            myShopping.PrintList();
            Console.ReadLine();
        }
        /// <summary>
        /// 商品类
        /// </summary>
       public class Goods
       {
           /// <summary>
           /// 商品名称
           /// </summary>
           private string name;           public string Name
           {
               get { return name; }
               set { name = value; }
           }
           /// <summary>
           /// 商品价格
           /// </summary>
           private double price;           public double Price
           {
               get { return price; }
               set { price = value; }
           }
       }
        /// <summary>
        /// 购物类
        /// </summary>
       public class Shopping
       {           private string list;           public string List
           {
               get { return list; }
               set { list = value; }
           }
           Goods[] goodsList;           internal Goods[] GoodsList
           {
               get { return goodsList; }
               set { goodsList = value; }
           }
           private void Inital()
           {
               this.GoodsList = new Goods[3];
               this.GoodsList[0] = new Goods();
               this.GoodsList[0].Name="农夫山泉";
               this.GoodsList[0].Price=1.02;
               this.GoodsList[1]=new Goods();
               this.GoodsList[1].Name="今麦郎碗面";
               this.GoodsList[1].Price=3.5;
               this.GoodsList[2]=new Goods();
               this.GoodsList[2].Name="双汇火腿肠";
               this.GoodsList[2].Price=12.6;
           }
           private void ShowGoodsInfo()
           {
               Console.WriteLine("{0,-4}\t{1,-8}\t{2:0.00}","编号","商品名称","单价");
               for (int i = 0; i < this.GoodsList.Length; i++)
               {
                   Console.WriteLine("{0,-4}\t{1,-8}\t{2:0.00}",i+1,this.GoodsList[i].Name,this.GoodsList[i].Price);
               }
           }
           public void PrintList()
           {
               this.Inital();
               this.ShowGoodsInfo();
               int a, b;
               int count = 0;
               string c = "";
               do
               {
                   Console.Write("输入商品编号：");
                   a = Convert.ToInt32(Console.ReadLine());
                   Console.Write("输入购买数量：");
                   b = Convert.ToInt32(Console.ReadLine());
                   Console.Write("输入e停止购物，输入其他任意继续购物:");
                   c = Console.ReadLine();
                   count++;
               } while (!c.Equals("e"));
               double sum = 0.0;
               this.List = "\n\n-----------欢迎光临光辉超市--------------";
               this.List = string.Format("{0}\n{1,-8}\t{2,-4:F2}\t{3,-4}\t{4,-4:F2}",this.List,"商品名称","单价","数量","小计");
               for (int i = 0; i < this.GoodsList.Length; i++)
               {
                   this.List = string.Format("{0}\n{1,-8}\t{2,-4:F2}\t{3,-4}\t{4,-4:C2}",this.List,this.GoodsList[i].Name,this.GoodsList[i].Price,b,this.GoodsList[i].Price*b);
                   sum += this.GoodsList[i].Price * b;
               }
               Console.WriteLine(this.List);
               Console.WriteLine("\n\n总计:{0}",sum);
           }
           }
       }
    }
运行后会出现数量是默认的1.求修改后的代码！

Answer 1

急用 谢谢  麻烦大大们帮看下！