编辑代码

using System;

public class HelloWorld
{
    public static void Main()
    {
      int a,b;
       Console.WriteLine("请输入两个操作数");
       a=Convert.ToInt32(Console.ReadLine());
       b=Convert.ToInt32(Console.ReadLine());
       Console.WriteLine("请输入运算符(+、-、*、/、)");
       string c=Console.ReadLine();
       switch(c){
           case"+":
           Console.WriteLine("{0}{1}{2}={3}",a,c,b,a+b);
           break;
            case"-":
           Console.WriteLine("{0}{1}{2}={3}",a,c,b,a-b);
           break;
            case"*":
           Console.WriteLine("{0}{1}{2}={3}",a,c,b,a*b);
           break;
            case"/":
           if(a==0||b==0){
              Console.WriteLine("不能为0"); 
           }
           else{ Console.WriteLine("{0}{1}{2}={3}",a,c,b,((double)a/b).ToString("F2"));
           }
           break;
           default:
           break;

       }
       Console.ReadLine();
    }
}