How do you declare an interface in C++?

Question

How do I setup a class that represents an interface? Is this just an abstract base class?

Answer 1

The whole reason you have a special Interface type-category in addition to abstract base classes in C#/Java is because C#/Java do not support multiple inheritance.

C++ supports multiple inheritance, and so a special type isn't needed. An abstract base class with no non-abstract (pure virtual) methods is functionally equivalent to a C#/Java interface.