A simple quick sort in PHP

Quick sorting is achieved by continuously locating the position of the reference number

/**
 * Created by PhpStorm.
 * User: saint
 * Date: 15/8/5
 * Time: 上午11:49
*/
class Demo
{
 public $a = array(3, 6, 9, 2, 4 , 7, 1, 5, 8, 0);

 public function qsort($left, $right)
 {
 if($left > $right) {
 return;
 }

 $i = $left;
 $j = $right;
 $standard = $this->a[$left];

 while($i != $j) {

 // Find units smaller than the base number from right to left
 while(($standard <= $this->a[$j]) && ($j > $i)) {
 $j--;
 }

 // Find the standard number from left to right Big
 while(($standard >= $this->a[$i]) && ($j > $i)) {
 $i++;
 }

 $tmp = $this->a [$i];
 $this->a[$i] = $this->a[$j];
 $this->a[$j] = $tmp;
 }

 // OK The position of the base number
 $this->a[$left] = $this->a[$i];
 $this->a[$i] = $standard;

 $this->qsort ($left, $i - 1);
 $this->qsort($i + 1, $right);
 }

 // Execute function
 public function main()
 {
 $left = 0;
 $right = count($this->a) - 1;
 $this->qsort($left, $right);
 print_r($this->a);
 }
}

$demo = new Demo();
$demo->main();

From: http://my.oschina.net/liuke1556/blog/488215

PHP