using System;

​

public interface IThing

{

}

​

public class IntThing : IThing

{

}

​

public class FloatThing : IThing

{

}

​

public class C 

{

    public static string func(IThing t) 

    {

        switch(t)

        {

            case IntThing : return "This is an IntThing";

            case FloatThing :  return "This is an FloatThing";

        };

​

        return "unknown";

    }

​

    public static void Main()

    {

        IThing t = new IntThing();

        Console.WriteLine("{0}", func(t));

    }

}