Thread: Creating Objects On The Heap And Adding Them To A List

Hi, I'm just starting with c++. I would like to have my program create POSITION items on the fly and add them to a CArray or CTypedPtrList or anything that will hold them. I do "POSITION* pPos = new POSITION;" but I can't get from the pointer to a new object in the list. Any help would be appreciated.

Maybe you can study something about basic data structures, like array, heap, binary tree, linked list.. I recommend you to read essays on www.aihorizon.com or maybe you can find something on this site.

If you want to have a linked list, for example

Code:

class List {
private:
  Node *root;
  Node *end;

public:
  List(void) { root = end = NULL; };
  void add(int value);

}

void List::Add(int value)
{
  if (root == NULL) {
    end = root = new Node;
    end->data = value;
    end->next = NULL;
    return; 
  } 
  end->next = new Node;
  end = end->next;
  end->data = value;
  end->next = NULL;  
}

every node should be something like

Code:

class Node {
private:
  int data;
  Node *next;

friend class List;
}

This code is not optimal, you can make it shorter and more efficient and so. Just study some materials and practise...

there are a number of ways to do this, depending on what you have available. One way is to use an STL list:

Code:

#include <list>
#include <vector>
.
.
.
class Position
{
  public:
    int x;
    int y;
}
.
.
.
int main()
{
  Position * ptr;
  list <Position *> myList;
  ptr = new Position;
  ptr->x = 1;
  ptr->y = 1;
  myList.push_back(ptr);//or myList.push_front(ptr) or myList.insert(//whatever);
.
.
.
  vector <Position *> v;
  v.push_back(ptr);//or whatever;

I suspect CArray or CTypedPtrList has something to do with VC++/MFC but since I don't use them I'm not sure about that. If your compiler is STL compliant a variation of the above should work, unless you are trying to get practice in creating your own list structure; in which case the example from mazo is a good place to start.