Inheritance in C++ multiple class issue

Question

just a very simple question regarding inheritance in c++.

let's say I have a few classes.

Class A inherits from class B and from class C.

I want to make class D inherit from class A , but the functionality of class C is breaking my code.

Is it possible to somehow exclude class C when I inheriting from class A in class D?

edit:

@Quentin

I'm using SFML and class A inherits from the sf::NonCopyable class. Class A is the SceneNode class on which the hierarchy for all entities/objects in the game world is based. I was making a "TileEngine" class that produces instances of "TileLayer" objects and I wanted the TileLayers to inherit from SceneNode so that I can pass drawing calls onto them through the hierarchy but since they're non copyable I can't fit them into a container and iterate through them in the TileEngine class.

But I think you're right, it doesn't truly break the code. I think I'll just need to add a few variables and come up with a book keeping system to make it work.

I was just curious if what I asked was possible since it'd be an easy solution and I don't know all the ins and outs of using inheritance yet, so even though it seemed unlikely I decided to check. Thx for the replies I think I'll be able to adapt the code on my own.

Answer 1

Nope.

Your A is both a B and a C .
If D cannot be a C , then it cannot be an A either.
Maybe use composition instead?

---

Update based on your specific case: There are a couple of ways that you can sort this out.

First off, does a SceneNode really need to be non-copyable, and if so, why? If this is a pure design decision, it is now apparent that it was the wrong one, since you're now in need of a copyable SceneNode . If the decision is technical (for example, there is bookkeeping data that is hard to clone correctly), you can try solving that problem. Failing that...

Could your SceneNode be movable instead? Move semantics are generally simpler than copy semantics to implement, and standard containers are perfectly happy with movable-only values. But even in that case...

Could your SceneNode be a simple interface instead? You only mention being able to call a drawing function. This does not sound related to any copying business, so maybe an interface with a pure virtual draw function is all you need. Otherwise...

If you really can't budge these requirements (at which point I would be surprised, but let's pretend), you can simply use a container of std::unique_ptr<TileLayer> . These don't require anything from their pointee, and can be stored in containers at will.

And then there's a whole 'nother batch of techniques that could fit you case. Don't forget that OOP and inheritance are just one way to crack that nut, but C++ offers many more tools and techniques besides it. But first, make it work :)