输入一个数n，求1-n的阶乘的和

Posted 2020-07-02 凌零聆

           while (true)
            {
                Console.WriteLine("请输入一个数n：");
                int n = int.Parse(Console.ReadLine());
                int sum = 0;
                for (int i = 1; i <= n; i++)
                {
                    int s = 1;
                    for (int a = 1; a <= i; a++)
                    {
                        s = s * a;
                      }
                    sum = sum + s;
                }
                Console.WriteLine("1-"+n+"的阶乘的和为："+sum);
                Console.ReadLine();
            }