C#字符拼接

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace x180821汪敏
{
    class Program
    {
        static void Main(string[] args)
        {
           /* Console.WriteLine("请输入您的姓名，性别和c#成绩");
            String name;
            char sex;
            double score;
            name = Console.ReadLine();
            sex = Convert.ToChar(Console.ReadLine());
            score = Convert.ToDouble(Console.ReadLine());
            Console.WriteLine("姓名:"+name+"\t"+"性别:"+sex+"\t"+"c#成绩:"+score);
            int a = 2;
            a++;
            int j, k;
            j = a++;
            k = ++a;
            Console.WriteLine(j*2);
            Console.WriteLine(k*2);
             */
            double pricep =25, priceb=3, pricec=10;
            int nump=20, numb=10, numc=5;
            double sump, sumb, sumc;
            sump = pricep * nump;
            sumb = priceb * numb;
            sumc = pricec * numc;
            double sum1 = sump + sumb + sumc;
            double sum2 = sum1 * 0.9;
            int k=(int)(sum2 / 100);
            int jf=k*3;
            Console.WriteLine("*************消费*************");
            Console.WriteLine("品名"+"\t"+"单价"+"\t"+"数量"+"\t"+"金额");
            Console.WriteLine("钢笔" + "\t" + "￥" + pricep + "\t" + nump + "\t" + sump);
            Console.WriteLine("笔记本" + "\t" + "￥" + priceb + "\t" + numb + "\t" + sumb);
            Console.WriteLine("书架" + "\t" + "￥" + pricec + "\t" + numc + "\t" + sumc);
            Console.WriteLine("******************************");
            Console.WriteLine("金额总计"+"￥"+sum1);
            Console.WriteLine("折扣：9折");
            Console.WriteLine("实付金额："+sum2);
            Console.WriteLine("本次所获积分是："+jf);
        }
    }
}