void insertion_sort (value_t** A, int n, 
                     int (*cmp_fptr)(const void*,const void*))
{
  printf ("--- Insertion sort! ---\n");
  int i, k; 
  value_t* tmp;
  i = 0;
  for ( k=1; k<n; k++ ) {
	  tmp = A[k];
	  i = k;
	  
	  while (i > 0 && cmp_fptr(A[i-1], tmp)) {
		  A[i] = A[i-1];
		  i--;
	  }
	  
	  A[i] = tmp;
  }
  
}