一、题目
4-1:利用静态方法，从优化程序性能的角度来计算1！+2！+……+N！的值。
二、我的努力
namespace 书本练习题
{
    public class Numbercount
    {
        public static int sumhe;
        public static int sum(int x)
        {
            int m=0,n=1;
            for(int i=1;i<=x;i++)
            {
                for(int j=1;j<=i;j++)
                {
                    n=n*j;
                }
                m=m+n;
                n = 1;
            }
            return m;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Console .WriteLine ("请输入一个大于1的正整数：");
            int number = Convert .ToInt32 (Console .ReadLine ());
            Numbercount .sumhe = Numbercount .sum (number );
            Console.WriteLine ("{0}!的值为：{1}",number ,Numbercount .sumhe);

            Console.ReadKey();
        }
    }
}

三、困惑
题目的要求是，从优化程序的角度计算阶乘的值。我不知道该如何做？请高手大侠们赐教，小虾在此有礼了。先谢谢了！

大家好
------
有网上高手已经帮我解决这个问题。现将代码公布如下：
namespace 书本练习题
{
    public class Numbercount
    {
        public static int sum(int x)
        {
            int m = 0, n = 1;
                for (int i = 1; i <= x; i++)
                {
                    n = n * i;
                    Console.WriteLine("值为：{0}",n);
                    m = m + n;
                }
            return m;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Console .WriteLine ("请输入一个大于1的正整数：");
            int number = Convert .ToInt32 (Console .ReadLine ());
            int sumber = Numbercount .sum (number );
            Console.WriteLine ("{0}!的值为：{1}",number ,sumber);

            Console.ReadKey();
        }
    }
}