**问题描述:**计算n的阶乘。
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace Test_01{class Program{public double Caculate(int num){switch (num){case 1:return 1;default:return num * Caculate(num - 1);}}static void Main(string[] args){int demo = int.Parse(Console.ReadLine());Program program = new Program();double Mid = program.Caculate(demo);Console.WriteLine(\"输出结果为:\"+Mid );Console.ReadLine();}}}