using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        int[] vectorA = {0, 2, 4, 5, 6};

        int[] vectorB = {1, 3, 5, 7, 8};

​

        var dotProduct = vectorA.Combine(vectorB, (a, b) => a * b).Sum();

​

        Console.WriteLine("Dot product: {0}", dotProduct);

​

​

    }

}

​

public static class CustomSequenceOperators

    {

        public static IEnumerable<S> Combine<S>(this IEnumerable<S> first, IEnumerable<S> second, Func<S, S, S> func)

        {

            using (IEnumerator<S> e1 = first.GetEnumerator(), e2 = second.GetEnumerator())

            {

                while (e1.MoveNext() && e2.MoveNext())

                {

                    yield return func(e1.Current, e2.Current);

                }

            }

        }

    }