using System;

using System.Collections.Generic;

using System.Linq;

​

public static class ExtenstionArray

{

    public static void ForEach<T>(this IEnumerable<T> sequence, Action< T, int> action)

    {

        int i = 0;

        foreach (T item in sequence)

        {

            action(item,i);

            i++;

        }

    }

}

​

public class Program

{

​

    public static void Main()

    {

         object[] arr = new object[] {1,2 };

            arr.ToList().ForEach((i, idx)=>{

                if(idx == 0)

                     Console.WriteLine("this is 0");

                else

                     Console.WriteLine(i);

            });

​

    }

}