// Source: "Software Design ...", John A Robinson, Newnes, 2004, page 229.
void merge(int *astart, const int *aend, int *bstart, const int *bend, int *out)
	{
	while ((astart < aend) && (bstart < bend))
		{
		if (*astart < *bstart)
			*out++ = *astart++;
		else
			*out++ = *bstart++;
		}
	while (astart < aend)
		*out++ = *astart++;
	while (bstart < bend)
		*out++ = *bstart++;
	}
int sort(int *array, int n)
	{
	int mid;
	extern int *buffer;	// Temporary global storage, same size as original array
	mid = n/2;
	if (mid == 0)
		return(0);
	sort(array, mid);
	sort(array+mid, n-mid);
	merge(array, array+mid, array+mid, array+n, buffer);
	memcpy(array, buffer, n*sizeof(int));
	return(0);
	}