using System;

using System.Collections;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        List<string> strings = new List<string> { "asd", "gdfd", "asda" };

        int order = 0;

        List<int> indexes = strings.Select(x => order++).ToList();

        foreach (int index in indexes)

        {

            Console.WriteLine(index);

        }

    }

}