Question

I am programming in C++ and cant figure out how to access the STL container in a parent class. I have the following classes:

class Card
class CardPile : private vector<Card*>
class Deck : public CardPile{Foo()}

I know that if Foo() was in CardPile class I can call vector’s size with size(). How would I call vector’s size() function from Foo().

EDIT: Unfortunately, I am not allowed to change any of the class definitions

Answer 1

size() is a private method of CardPile, but you could, it if suits the design, make it public or protected:

class CardPile : private std::vector<Card*>
{
 public: // or protected
  using std::vector<Card*>::size;
};

This will allow you to call size() either everywhere (public) or from derived classes (protected).

But bear in mind that standard library containers are not designed to be inherited from, specially publicly. So you could change your CardPile class to hold a std::vector<Card*> data member. And after that, you may look into holding smart pointers in the vector if you are currently dealing with dynamically allocated Card objects.

class CardPile : 
{
 public: // or protected
  std::vector<Card*>::size_type size() const { return cards_.size(); }
 private: 
  std::vector<Card*> cards_
};