trouble deleting at array of arrays

[S8hvC542]

I have an array of arrays. When needed I allocate as shown as follows. With this allocation method, I am able to access the values using normal array notation:

histogram[i][i] = blah blah;

if (histogram == 0) {
  histogram = new int*[bytesPerPixel];

  for (i = 0; i < bytesPerPixel; i++) {
    histogram[i] = new int[256];

    for (j = 0; j < 256; j++) {
      histogram[i][j] = 0;
    }
  }
} 

However, whenever I try to use the following code to delete the allocated memory, the execution simply returns "Aborted". Any ideas? It's got to be something simple, but I'm just not seeing it.

if (histogram != 0) {
  for (i = 0; i < bytesPerPixel; i++) {
    delete[] histogram[i];
  }
  delete[] histogram;
}

[chenqi07]

just write delete []histogram;

if (histogram != 0) {
  for (i = 0; i < bytesPerPixel; i++) {
    delete[] histogram[i];
  }

is not needed.

[S8hvC542]

Okay, that did not work, but I discovered something else. My destructor method (which is doing the memory deletion) is being called four times even though I only call it 3 times as I only had 3 objects.

My quick research tells me though that I should not be calling the destructor myself? Does C++ just take care of this for me since I explained how to delete my objects? I'm just surprised by this as I did not have this issue on another program I coded which called the destructor for each object I instantiated.

[chenqi07]

Oh,yes!!
Thank you for pointing out my mistake.
Try this.
Add histogram = NULL; after delete []histogram.

[S8hvC542]

Hmmm, I did NULL my other dynamic arrays, but forgot to for this particular one as you pointed out.

So the execution just bombs out because it finds a memory leak or something?

Thanks for the help.

[helios]

The for loop that deletes each of the elements in histogram is needed.

I can't find anything in the code that could cause the problems you're seeing. AFAICT, this code is correct.

[S8hvC542]

Thanks guys for the help.

I went back to

if (histogram != 0) {
  for (i = 0; i < bytesPerPixel; i++) {
    delete[] histogram[i];
  }
  delete[] histogram;
}

and it works now fine even with the second "delete" which is not in the for loop. It seems my only mistake was not including

histogram = NULL;