note 11831 deleted from language.functions by felipe

Note Submitter: yasuo_ohgaki at hotmail dot com 

----

PHP supports recursion. I thought it worth to mention.

Simple Quick Sort using recursion works perfectly.

== OUTPUT ==
Recursion TEST

Array
(
    [0] => 12
    [1] => 23
    [2] => 35
    [3] => 45
    [4] => 56
    [5] => 67
)
== END OUTPUT ==

== QUICK SORT CODE ==
<?php

echo('<br>Recursion TEST<br>');

function swap(&$v, $i, $j) {
 $temp = $v[$i];
 $v[$i] = $v[$j];
 $v[$j] = $temp;
}

// Quick Sort integer array - $int_array[$left] .. $int_array[$right]
function qsort(&$int_array, $left, $right) {
 if ($left >= $right)
  return; // Do nothing if there are less than 2 array elements
 swap ($int_array, $left, intval(($left+$right)/2));
 $last = $left;
 for ($i = $left + 1; $i <= $right; $i++)
  if ($int_array[$i] < $int_array[$left])
   swap($int_array, ++$last, $i);
 swap($int_array, $left, $last);
 qsort($int_array, $left, $last-1);
 qsort($int_array, $last+1, $right);
}

$val = array(56,23,45,67,12,35);

qsort($val, 0, count($val)-1);

echo '<pre>';
print_r ($val);
echo '</pre>';

?>
== END QUICK SORT ==