Question about inheritance

[translore]

I have a base class called Node. Inside the class I have a data member that is a vector to keep track of children. I want to make a derived class called LeafNode. I don't want the leaf node to inherit the vector. How do I stop it?

class Node
{
...
private:
	vector <Node*> myChildren; // I don't want my derived class LeafNode to inherit this
};

[kevinchkin]

It will not inherit that member. As that member is private.

[translore]

Oh I see. Another question would be is it always a good practice to make every data member private or have some public to be inherited or is that bad?

[Disch]

Errr....

It does inherit private stuff. It just can't access it. However it could still be accessed by public/protected member functions of the parent class.

You cannot prevent a child class from inheriting some stuff from its parents -- it's all or nothing. If you don't want a class to have some information you need to design your hierarchy differently. Perhaps derive them both from an abstract base:

class NodeBase
{
public:
  // stuff for all types of nodes
};

class Node : public NodeBase
{
private:
  vector<NodeBase*> myChildren;
};

class LeafNode : public NodeBase
{
 // class can have all the same member functions that NodeBase has, but
 // will not have the vector that Node has
};

I usually go protected for most things that aren't public in my classes, simply because I may choose to derive another class from it which does something similar in the future. I use 'private' mostly for classes which I know will have children, and I want some stuff intentionally hidden from them. I can't really come up with good specific examples.

Anyway if you aren't planning on having any children for a class -- choosing between private/protected isn't really all that important IMO.