using System;

using System.Collections;

namespace YieldDemo

{

    class Program

    {

        public static IEnumerable Power(int num, int exponent)

        {

            int counter = 0;

            int result = 1;

            while (counter++ < exponent)

            {

                //if (counter == 4) yield break;

                if (counter == 4) yield return null;

                result = result * num;

                yield return result;

            }

        }

        public static IEnumerator Power2(int num, int exponent)

        {

            int counter = 0;

            int result = 1;

            while (counter++ < exponent)

            {

                //if (counter == 4) yield break;

                if (counter == 4) yield return null;

                result = result * num;

                yield return result;

            }

        }

        static void Main(string[] args)

        {

            foreach (var item in Power(2,8))

            {

                Console.WriteLine(item);

            }

            Console.WriteLine("---");

            var e = Power2(2, 8);

            while (e.MoveNext())

            {

                var i = e.Current;

                Console.WriteLine(i);

            }

            Console.WriteLine("main done");

            Console.ReadKey();

        }

    }

}