Can't delete dynamically allocated multidimensional array

Question

I can't delete the dynamically generated arrays. There is how I create them:

template <typename T>
T **AllocateDynamic2DArray(int nRows, int nCols){
      T **dynamicArray;

      dynamicArray = new T*[nRows];
      for( int i = 0 ; i < nRows ; i++ ){
        dynamicArray[i] = new T[nCols];
        for ( int j=0; j<nCols;j++){
                dynamicArray[i][j]= 0;
            }
        }
      return dynamicArray;
}

And I initialize a 2D array using:

long double** h = AllocateDynamic2DArray<long double>(KrylovDim+1,KrylovDim);

I can't delete it. Here are the variations that I've tried:

delete[] h;

and it gives the error: "cannot delete objects that are not pointers" when I apply this:

   for (int qq=0; qq < KrylovDim+1; qq++){
        for (int ww=0; ww < KrylovDim; ww++){
            delete [] h[qq][ww];
        }
        delete [] h[qq];
    }

Is there any way for a clean delete? I'm using visual studio 2010 if it helps.

Easy way to figure this out: you must have exactly one (not more, not fewer) delete, for every new. In your allocation, you invoke new 1+nRows times. How many times do you invoke delete? — Robᵩ
– Robᵩ, Commented Apr 29, 2011 at 19:07

Pepe · Accepted Answer · 2011-04-29 19:04:03Z

4

Try this:

for (int qq=0; qq < KrylovDim + 1; qq++)
{
    delete [] h[qq];
}
delete [] h;

So basically you are doing the reverse of the allocation process

for( int i = 0 ; i < nRows ; i++ ){
    dynamicArray[i] = new T[nCols]; // Instead of allocating now delete !

edited Apr 29, 2011 at 19:04

answered Apr 29, 2011 at 18:57

Pepe

6,4805 gold badges29 silver badges29 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Pepe Over a year ago

@Emre np. Sorry for the multiple edits but I was juggling somethings at the same time :)

Emre Turkoz Over a year ago

R: so you start deleting by the outermost dimension? if it was a 4D array, we would have 3 loops to delete and 1 delete[] h. cool.

Pepe Over a year ago

@Emre yup... basically just do the exact reverse of the allocation process.

Collectives™ on Stack Overflow

Can't delete dynamically allocated multidimensional array

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related