找出100以内的质数并求和

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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
           int a = 0;
                for(int s=0;s<=100;s++)
                {
                 int num = 0;//记录能整除的数的个数

                 for (int i = 1; i <= s; i++)
                 {

                     if (s % i == 0)
                     {
                         num++;
                     }
                 }
                     if (num == 2)
                     {

                         Console.WriteLine(s);
                         a = a + s;
                     }

                }
                Console.WriteLine("100以内所有质数和为{0}",a);
                Console.ReadLine();
        }
    }
}