In Visual Studio 2015 or later, I can open the ‘C# interactive window’, and run code:
> 5 + 3
8
That’s cute. Now how can I interact my code—my classes? Assume I have a project open.
> new Cog()
(1,5): error CS0246: The type or namespace name 'Cog' could not be found (are you missing a using directive or an assembly reference?)