*/ function add($n, $k) { // adds $k to $n by calling successor. echo " add called with n = " . $n . " and k = " . $k . ". "; $i = 0; echo "i = ". $i . ". "; while ($i < $k) { $n = successor($n); $i = successor($i); echo "i = " . $i . "\t k = " . $k . "\t n = " . $n . " "; } return $n; } //@TODO add comments to the above function, describing what each line of the above function does?