using System;

​

interface ITest

{

    void Test();

}

​

class Service : ITest

{

    public void Test(){}

    public void Fun(){}

}

​

class Client

{

    ITest objRef;

    public Client(ITest objRef)

    {

        this.objRef=objRef;

    }

    public void InvokeService()

    {

        objRef.Test();

    }

}

​

public class Program

{

    public static void Main()

    {

        Service _serviceRef=new Service();

        Client _clientRef=new Client(_serviceRef);

        _clientRef.InvokeService();

    }

}