迭代器数素数,这个是我抄《C#入门经典》的
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;

namespace 迭代器数素数
{
    public class Primes
    {
        private long min;
        private long max;

        public Primes()
            : this(2, 100)
        {
        }
        public Primes(long minium, long maximum)
        {
            if (minium < 2)
                minium = 2;

            min = minium;
            max = maximum;
        }

        public IEnumerator GetEnumerator()
        {
            for (long i = min; i < max; i++)
            {
                bool isPrime = true;
                for (long j = 2; j <= (long)Math.Sqrt(i); j++)
                {
                    long result;
                    result = i % j;
                    if (result == 0)
                    {
                        isPrime = false;
                        break;
                    }
                }
                if (isPrime)
                    yield return i;
            }
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            long min,max;

            Console.WriteLine("这是一个可以告知在一个确定范围内所有素数的程序。");
            Console.WriteLine("请输入下限：");
            min=Convert.ToInt64(Console.ReadLine());
            Console.WriteLine("请输入上限：");
            max=Convert.ToInt64(Console.ReadLine());

            Primes myPrime = new Primes(min, max);
            Console.WriteLine("以下是计算后得到的结果：");
            foreach (long Prime in myPrime)
                Console.WriteLine(Prime);

            Console.WriteLine("谢谢使用。");
            Console.ReadKey();
        }
    }
}

貌似你什么都知道 还要问别人