using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        List<int> list = DataFields("101111111011111110111111");

        list.ForEach(l => 

        {

            Console.WriteLine(l.ToString("X"));

        });

    }

​

    public static List<int> DataFields(string binary)

    {

        List<int> result = new List<int>();

​

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

        {

            if (binary[i] == '1')

            {

                result.Add(i + 1);

            }

        }

​

        return result;

    }

}