Question

I was solving some simple pointer exercises when i came across the following example:

void deallocate2D(int** array, int nrows) {     
 /*  deallocate each row  */
 int i;
 for(i = 0; i < nrows; i++) {
      free(array[i]);
 }

 /*  deallocate array of pointers  */
 free(array);     
}

The array is defined in main as int** array1;

Is this a correct way of deallocating memory of a 2d array or should an int*** array be passed in the function instead?
Is there a way to check that memory has been successfully deallocated?

Answer 1

Yes, that’s correct. int*** is only necessary if you intend to change the value of the pointer, which you don’t need to.

There do exist tools which can check your memory allocations/frees – Valgrind should be able to do it.