using System;

using System.Collections.Generic;

using System.Threading;

using System.Threading.Tasks;

​

namespace ConsoleApplication1

{

    internal class Program

    {

        public static Dictionary<int,int> res = new Dictionary<int,int>(){

            [5]= 0,

            [6]= 0,

            [7]= 0,

            [8]= 0,

            [9]= 0

        };

        static int myFatorFun2(int n)

        {

            if (n == 0)

                return 1;

            int temp = myFatorFun2(n - 1) * n;

          //  Console.WriteLine("计算结果是：" + temp.ToString());

            res[n] = temp;

            return temp;

        }

        static Task<int> GetTask(int n){    

            Task<int> t = Task.Run<int>(()=>{

                Console.WriteLine("Task thread is " + Thread.CurrentThread.ManagedThreadId);

                int r = myFatorFun2(n);

                Console.WriteLine(n + " 计算结果是：" + r);

                return r;

            });

            return t;

        }

        static async Task<int> GetFactor(int n){

            Console.WriteLine("GetFactorStart for : " + n + ". Thread is " + Thread.CurrentThread.ManagedThreadId);

            int r = await GetTask(n);

            Console.WriteLine("GetFactorEnd for : " + n + ". Thread is " + Thread.CurrentThread.ManagedThreadId);

            return r;

        }

        static void Main(string[] args)

        {

            Console.WriteLine(Thread.CurrentThread.ManagedThreadId);

            int[] a = new int[5] {5,6,7,8,9};

            foreach (int n in a){

                 GetFactor(n);

                //Console.WriteLine("v: " + v);

            }

            Console.WriteLine("END");

            Thread.Sleep(1000);

        }

​

    }

}

​