补充一下，没写分号：
//定义变量接收两个数的运算结果
int t=0;

恩   switch case语句也可以

哎呀嘞，这个问题 值得怎么多人讨论吗？？？？？？？？

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

namespace 判断对错
{
    class Program
    {
        static void Main(string[] args)
        {
           int sum1=0;
            int sum = 0, cha = 0, ji = 0, yu = 0;
        x:
            {
            Console.Write("请输入一个整数：");
            int i = int.Parse(Console.ReadLine());
            Console.Write("请再输入一个整数：");
            int j = int.Parse(Console.ReadLine());
            Console.WriteLine("请输入你想求什么值（+，-，*，/）");
            char op = char.Parse(Console.ReadLine());
            Console.Write("{0}{1}{2}"+"=",i,op,j);
            int s =int.Parse(Console.ReadLine());
            switch(op)
            {
                case '+':
                    sum=i+j;
                    break;
                    
                case '-':
                    cha=i-j;
                    break;
                case'*':
                    ji=i*j;
                    break;
                case'/':
                    yu=i/j;
                    break;
            }
            if(s==sum||s==cha||s==ji||s==yu)
            {
                Console.WriteLine("答案正确！！");
                sum1++;
            }
           }
           Console.WriteLine("你想继续答题？（y/n）");
           char op1 = Char.Parse(Console.ReadLine());
           if (op1 == 'y' || op1 == 'Y')
           {
               goto x;
           }
           

            Console.WriteLine("答对的题目数为{0}",sum1);
            Console.ReadLine();

        }
    }
}