pointing to object within an vector

[rozick1]

Hi

I have the following classes:

  //Player.cpp
  #include "Piece.h"

  Piece* Player::addPiece (Chesspiece type)
{
	Piece new_piece (type,this);  //create new piece which points back to Player object
	pieces.push_back (new_piece); //copy piece to vector of pieces held by Player

	return pieces[pieces.size()-1].getPtr(); //once added return a pointer to the new piece
}

  //Piece.cpp

Piece::Piece (Chesspiece init,Player *parent)
{
	moved = false;
	taken = false;
	type = init;
	player = parent;
}

Piece* Piece::getPtr() //return pointer to Piece object
{
	return this;
}

However, when I've tested this out:

int main()
{
	Player test ("test",Bottom);
	Piece* p1 = test.addPiece(Queen);
	Piece* p2 = test.addPiece(Pawn);
	std::cout << p1->getType()<<std::endl;
	std::cout << p2->getType()<<std::endl;
}

I get the following output:

11754464
5

The first number is garbage (and varies every time) and the second number is correct.

Any ideas what I'm doing wrong? I suspect its something to do with the vector and that the pointer changes when its resized but would be grateful for any thoughts.

I've not tried this yet but should I create a vector of points to dynamically allocated Piece objects?

Thanks

[cire]

If you're storing pointers to elements in a vector, then yes, if adding an element to a vector results in a reallocation, those pointers are invalidated. The simplest solution would be to use a std::dequeue in place of the std::vector. You can probably drop that in without changing any other code.