Derived vector of Ptrs

[UglyIgloo]

I'm currently trying to find a list of derived classes in a list of unique_ptr<BaseClass>(Ptr from now on). Problem is, it can't convert the derived class into a Ptr. Here's the code.

Ptr declaration

class cSceneNode
{
typedef std::unique_ptr<cSceneNode>		Ptr;
std::vector<Ptr>			mChildren;
}

Derived class

class cEntity
	:public cSceneNode
{
public:
	void				move(sf::Vector2f Pos);
}

Void move, A.K.A. derived members of mChildren

void cEntity::move(sf::Vector2f Pos)
{
	mSprite.move(Pos);

	for each(cEntity* _child in mChildren)
	{
		_child->move(Pos);
	}
}

Now, here's the thing. Back when mChildren was just a vector of raw pointers (Yeah, I know, bad practice), I could easily access the cEntity's in the vector. I really don't want to use casting, but if there's some other way, please let me know. Thanks.

[ne555]

> I really don't want to use casting
guess what, you were doing it.


http://en.wikipedia.org/wiki/Liskov_substitution_principle
Preconditions cannot be strengthened in a subtype.
`mChildren' holds pointer to `CSceneNode' but you are treating it as if contains pointers to `CEntity'

[UglyIgloo]

So how can I loop through the Entities in the vector like I did with raw pointers?

[UglyIgloo]

Bump because it's buried to the second page.

I'm honestly not really sure what to do about this other than stop using smart pointers, but if I do that, using a vector of raw pointers is going to be a pain to allocate. I've tried Googling my problems, but from what I've seen, I'm literally the only person who has ever thought about iterating over a derived type in a list of a base type.


EDIT:


Should be noted that as of the 2015 Vocabulary Reformation Act, literally now means figuratively.