using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var input = "asd sdf dfg";

        var stringList = new List<string>();

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

        {

            for (int j = i; j < input.Length; j++)

            {

                var substring = input.Substring(i, j-i+1);

                stringList.Add(substring);

            }

        }

        foreach(var item in stringList)

        {

            Console.WriteLine(item);

        }

    }

}