using System;

​

public class Program

{

    public static void Main()

    {

        IPictureService service = new CdnPicutreService();

        service.SaveImage();

        service = new DbPicutreService();

        service.SaveImage();

    }

}

​

public interface IPictureService

{

    void SaveImage();

}

​

public class CdnPicutreService : IPictureService

{

    public void SaveImage()

    {

        Console.WriteLine("Picture saved in Cdn!");

    }

}

​

public class DbPicutreService : IPictureService

{

    public void SaveImage()

    {

        Console.WriteLine("Picture saved in Db!");

    }

}