using System;

using System.Collections.Generic;

using System.Diagnostics;           

​

namespace Yields

{

​

public class Program

{

        static List<int> myList = new List<int>(); 

        static void FillData()

        {

            myList.Add(1);

            myList.Add(2);

            myList.Add(3);

            myList.Add(4);

            myList.Add(5);

​

        }

​

        public static void Main(string[] args)

        {

            FillData();

            foreach (var item in myList)

            {

                Console.WriteLine(item);

            }

            Console.WriteLine();

​

            //using tempdata

            Stopwatch stopwatchTempData = new Stopwatch();

            stopwatchTempData.Start();

            foreach (var item in IterateUsingTemp())

            {

                Console.WriteLine(item);

            }

            Console.WriteLine("Execution without yield "+stopwatchTempData.Elapsed);

            Console.WriteLine();

            //using yield

            Stopwatch stopwatchYield = new Stopwatch();

            foreach (var item in IterateStatefulYield())

            {

                Console.WriteLine(item);

            }

            Console.WriteLine("Execution using yield:" + stopwatchYield.Elapsed);

​

        }

​

        static IEnumerable<int> IterateUsingTemp()

        {

            List<int> tempdata = new List<int>();

​

            foreach (var item in myList)

            {

                if (item > 3)

                {

                    tempdata.Add(item);

                }

            }

            return tempdata; 

        }

​

        static IEnumerable<int> IterateStatefulYield()

        {

            foreach (var item in myList)

            {

                if (item > 3)

                {

                    yield return item;

                }

            } 

        }

}

}