using System;

​

public class Program

{

    public static void Main()

    {

        Client client = new Client(new Service());

        client.Start();

        NewService newService = new NewService();

        Client clientNewFunction = new Client(newService);

        clientNewFunction.Start();

​

    }

}

​

public interface IService

{

    void Serve();

}

​

public class NewService : IService

{

    public void Serve()

    {

        Console.WriteLine("I'm doing something NEW!!!!!!");

    }

}

​

​

public class Service : IService

{

    public void Serve()

    {

        Console.WriteLine("Service Called");

        //To Do: Some Stuff

    }

}

​

public class Client

{

    private readonly IService _service;

    public Client(IService service)

    {

        this._service = service;

    }

    public void Start()

    {

        Console.WriteLine("Service Started");

        this._service.Serve();

        //To Do: Some Stuff

    }

}

​

public class OldClient

{

    public OldClient()

    {

    }

​

    public void Start()

    {

        //Service WriteToDB = new Service();

        Service WriteToCloud = new Service();

        Console.WriteLine("Service Started");

        //WriteToDB.Serve();

        WriteToCloud.Serve();

    }

​

}

​

​