C# Task Task<TResult> 클래스 사용하기.

using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace ThreadNTask
{
    class Program
    {
        static void Main(string[] args)
        {
            long from = Convert.ToInt64(args[0]);
            long to   = Convert.ToInt64(args[1]);

            int taskCount = Convert.ToInt32(args[2]);

            Func<object, List<long>> FindPrintFunc = (objRange) =>
            { 
                long[] range = (long[])objRange;
                List<long> found = new List<long>();

                for(long i = range[0]; i < range[1]; i++)
                {
                    if(IsPrime(i))
                    { 
                        found.Add(i);
                    }
                }

                return found;
            };

            Task<List<long>>[] tasks = new Task<List<long>>[taskCount];

            long currentFrom = from;
            long currentTo   = to / tasks.Length;

            for(int i = 0; i < tasks.Length; i++)w
            {
                Console.WriteLine("Tasks[{0}] : {1} ~ {2}", i ,currentFrom, currentTo);
                tasks[i] = new Task<List<long>>(FindPrintFunc, new long[]{currentFrom, currentTo});
                currentFrom = currentTo + 1;

                if(i == tasks.Length - 2)
                {
                    currentTo = to;

                }
                else
                { 
                    currentTo = currentTo + (to / tasks.Length);
                }
            }

            Console.WriteLine("Please press enter to start");
            Console.ReadLine();
            Console.WriteLine("Started");

            DateTime startTime = DateTime.Now;

            foreach(Task<List<long>> task in tasks)
            {
                task.Start();
            }

            List<long> total = new List<long>();

            foreach (Task<List<long>> task in tasks)
            {
                task.Wait();
                total.AddRange(task.Result.ToArray());
            }

            DateTime endTime = DateTime.Now;

            TimeSpan ellapsed = endTime-  startTime;

            Console.WriteLine("Prime number between {0} and {1}", from, to, total.Count);

            Console.WriteLine("Ellapsed time: {0}", ellapsed);
        }

        static bool IsPrime(long number)
        { 
            if(number < 2)
            { 
                return false;
            }

            if(number % 2 == 0 && number != 2)
            { 
                return false;
            }

            for (long i = 2; i < number; i++)
            {
                if(number % i == 0)
                { 
                    return false;
                }
            }

            return true;
        }
    }
}