float row[] = { 1, 2, 3, 4, 5, 6, 7, 8 };

stdio:print ("%f" "\n", avg),
{
  avg = average (row, array_length (row))                                      /* "&row[0]" */
};

stdio:print ("%f" "\n", avg),
{
  avg = average (&row[3], array_length (row) - 4)                              /* "&row[3]" */
};