Question

I’m new to C++, and unfortunately I cannot stop thinking in C# (my former language).
I read some books, forums and the C++ reference website, but I couldn’t find an answer to my question, so I thought I might as well try here before giving up and writing something ugly.

Ok, we can start.
I have a class with an abstract method succesorsFunction and I would like it to return a collection of pointers to State. I don’t want to force the implementors to a specific container; I rather let them choose (vector, list, etc).

So it looks like this:

class Problem
{
public:
    virtual list<const State*>::iterator succesorsFunction(const State &state, list<const State*>::iterator result) const = 0;
};

the problem here is the explicit use of list. How do you do it in C++?

I thought about using templates, but then I encountered two problems:
1) It seems like you cannot do it with abstract methods (or am I wrong?)
2) How do I tell the template it should contain pointers to State?

Answer 1

You can’t overload methods based on return types in C++.

Also, “containers” in C++ don’t have the same base (like Collection in Java), so you can’t return a generic container.

I’m afraid there’s no clean way of doing this.

I would just write overloads (by parameter) or different function names.

For your questions:

1) You can. What makes you think you can’t?

2) The same way you declared list: list<const State*> – const is optional.