Segmenation Faults when using new and delete

Ok the red lines cause faults when they are not commented out.
Can anybody fix this?

Code:

//copy constructor
heap::heap(const heap &aHeap)
{
  delete [] heapArr;                                                                                                                        
  heapArr = NULL;                                                                                                                           

  cout << heapArr <<endl;
  heapArr = new HeapNode[aHeap.maxSize];
  if (heapArr != NULL)
  {
    maxSize = aHeap.maxSize;
    curSize = aHeap.curSize;
    for (int a = 0; a <= curSize; a++)
    {
      heapArr[a] = aHeap.heapArr[a];
    }
  }
  else
    maxSize = 0;
}


bool heap::buildHeap(HeapNode *n, const int nodes)
{

  //delete previous heap if one exists                                                                                                        
  if(curSize != 0)
  {
    delete [] heapArr;
    heapArr = NULL;
    curSize = 0;
    maxSize = 0;
  }
    cout << "reallocate" <<endl;
    cout << heapArr <<endl;
  heapArr = new HeapNode[nodes];
  cout << "after reallocate " <<endl;
  if (heapArr != NULL)
  {
    maxSize = nodes;
    for (int a = 1; a <= maxSize; a++)
    {
      cout << "begin copy" <<endl;
      heapArr[a] = n[a];
      curSize = a;
      percDown(a);
    }
    return true;
  }
  else
    maxSize = 0;
  return false;
}

> for (int a = 1; a <= maxSize; a++)
> {
> cout << "begin copy" <<endl;
> heapArr[a] = n[a];
Arrays start at 0. Here you are going one past the end of the array, as 0 is the first element, maxSize-1 is the last element. You probably have the same problem in your constructor.

It's a constructor, so by definition, nothing exists prior to being called.

Code:

//copy constructor
heap::heap(const heap &aHeap)
{
  delete [] heapArr;  // remove this line.
  heapArr = NULL;     // this does nothing useful. but it isn't harmful.

Originally Posted by Salem

It's a constructor, so by definition, nothing exists prior to being called.

Code:

//copy constructor
heap::heap(const heap &aHeap)
{
  delete [] heapArr;  // remove this line.
  heapArr = NULL;     // this does nothing useful. but it isn't harmful.

that what i thought about the constructor. I was using my professors code for a queue and she had it there( I think it caused a fault when i ran it). I sent her an email asking if I really need it already and am still waiting for a response.

Thanks for the reasurance about whether or not i needed that code

Originally Posted by swoopy

> for (int a = 1; a <= maxSize; a++)
> {
> cout << "begin copy" <<endl;
> heapArr[a] = n[a];
Arrays start at 0. Here you are going one past the end of the array, as 0 is the first element, maxSize-1 is the last element. You probably have the same problem in your constructor.

You're right arrays start at 0. I forgot that because for heaps my class has been taught to use 1 for the start. I needed something like:

Code:

 maxSize = nodes;
    for (int a = 0; a < maxSize; a++)
    {                                                                                                                                         
      cout << "begin copy" <<endl;
      heapArr[a+1] = n[a];
      curSize = a+1;
      percDown(a+1);
    }

Thanks for the reminder.

Now all I just need to get it to organize properly.

It should also be mentioned that on new compilers, testing the return value of new is unnecessary, as new either returns a valid pointer or throws an exception.