using System;

​

namespace ExtensionsConsoleApp

{

    public class Program

    {

        public static void Main(string[] args)

        {

            string s = "super string!";

            Console.WriteLine(s.AddToBegin("My first ")); //expected is 'My first super string'

        }

    }

}

​

namespace ExtensionsConsoleApp.Extensions

{

    /// <summary>

    /// String extension class.

    /// </summary>

    public class StringExtension

    {

        /// <summary>

        /// Adds <paramref name="startText"/> to begin of <paramref name="source"/> string.

        /// </summary>

        /// <param name="source">Source string</param>

        /// <param name="startText">Start text string</param>

        /// <returns>Returns riched string.</returns>

        public void AddToBegin()

        {

            //add code

        }

    }

}