using System;

public delegate void ItemFoundCallback(int index);

public static class ItemFinder {

    public static void FindItem (string[] list, string stringToFind, 

        ItemFoundCallback callback) {

        for(int i=0; i < list.Length; i++){

            if(list[i] == stringToFind)

                callback(i);

        }

    }

}

public class Program

{

    public static void Announce(int i) {

        Console.WriteLine("String found at index {0}!", i);

    }

    public static void Main()

    {

        string [] s = { "Pikachu" , "Squirtle" , "Ditto" ,

                       "Pikachu" , "Ditto" , "Dragonite" };

        Console.WriteLine("Finding Pikachu...");

        ItemFinder.FindItem(s ,"Pikachu" ,Announce);

        Console.WriteLine("Finding Ditto...");

        ItemFinder.FindItem(s , "Ditto", Announce);

    }

}