using System;

using System.Collections.Generic;

using System.Linq;

using static System.Console;

​

//C# 7 is coming soon in VS 2017

//Try out some of the new features without having to install VS 2017 RC

​

//Source 1: http://www.c-sharpcorner.com/article/top-10-new-features-of-c-sharp-7-with-visual-studio-2017/

//Source 2: https://docs.microsoft.com/en-us/dotnet/articles/csharp/csharp-7

 interface I{}

public class A:I{}

public class B:I{}

​

public class Program

{

    public static void Main()

    {

        I ob = new A();

        switch(ob) 

        {

            case A var :

                Console.WriteLine(ob);

                break;

            case B var :

                Console.WriteLine(ob);

                break;

        }

    }

}