using System;

using System.Linq;

using System.Collections.Generic;

​

public static class MyFunctions {

    public static void ForEvery(this List<int> source, Action<int> action){

        if(source == null)

            return;

        foreach(int item in source){

            action(item);

        }

    }

    public static void ForEveryGeneric<TSource>(this List<TSource> source, Action<TSource> action){

        if(source == null)

            return;

        foreach(TSource item in source){

            action(item);

        }

    }

}

public class Program

{

​

    public static void Main()

    {

        string name = "Douglas";

        List<int> numbers = new List<int>() {10, 30, 23, 59, 60};

        Console.WriteLine("-----Using built in ForEach method.-------");

        numbers.Where((number) => number % 10 == 0).ToList().ForEach((number) => { 

            Console.WriteLine(name + " " + number);

        });

        Console.WriteLine("-----Using explicit foreach keyword.-------");

        foreach (int number in numbers.Where((number) => number % 10 == 0)) {

            Console.WriteLine(name + " " + number);

        }

        Console.WriteLine("-----Using our ForEvery method.-------");

        numbers.ForEvery((number) => Console.WriteLine(name + " " + number));

    }

}