#include <stdlib.h>

/* expand() takes an existing malloc'd int array of size, and doubles it, 
   if possible.

   It returns 0 if successful, non-zero on failure (meaning the array
   was not expanded.
*/
   
int expand(int **array, int *size) {
  int *newp = 0;

  newp = (int *)realloc(*array, *size * 2 * sizeof(int));
  if (!newp)
    return(-1);

  *size *= 2;
  *array = newp;
  return 0;
}