c#实现：返回n到m之间的所有素数

 class Program
    {
        static void Main(string[] args)
        {
            Sushu();
        }
        public static void Sushu()
        {
            Console.WriteLine("请输入求素数的起始数字用','隔开：");
            string y = Console.ReadLine();
            Console.WriteLine("这个范围内的素数有：{0}", CalPrim(int.Parse(y.Split(',')[0]), int.Parse(y.Split(',')[1]), ""));   
        }
        public static string CalPrim(int x, int y, string sushu)
        {
            bool check = true;//是素数
            for (int i = 2; i < x; i++)
            {
                if (x % i == 0)
                {
                    check = false;
                }
            }

            if (check == true && x < y)
            {
                return CalPrim(x + 1, y, sushu += x + "、");
            }
            else if (check == false && x < y)
            {
                return CalPrim(x + 1, y, sushu);
            }
            else
            {
                return sushu;
            }
        }
        public static string GetSuShu2(int x, int y, string sushu)
        {
            int count = 0;
            for (int i = 1; i<=x; i++)
            {
                if (x%i==0)
    {
         count++;
    }
                if(count>2)
                    return CalPrim(x+1,y,sushu);
            }
            if(x<y){
                return CalPrim(x+1,y,sushu
                    +=x+"、");
            }
            else{
                return sushu;
            }
        }
    }