Problem with class

[Anon]

Hi.

I have this code
<?
class nodetree {
var $keywords;
var $Title;
var $child;
var $cnode;

  function add_child($Child) {
	if(empty($this->child)) {
		$nodenumber = 0;
	} else {
		$nodenumber = count($this->child);
	}
       echo "Agregar: $Child->keywords a $this->keywords;<BR>";
       $this->child[$nodenumber] = $Child; 
       $this->cnode++;
  }

  function add_childin($Child, $parent) {
           echo $this->keywords;
           if ($this->keywords==$parent) {
              $this->add_child($Child);
              return $this;
           }
           $i=0;
           while ($i<$this->cnode) {
                 $ptr=$this->child[$i];  
                 if ($ptr) { 
                    if ($ptr->add_childin($Child, $parent)) 
                       break;
                 }
                 $i++;
           }
 }

  function shownode() {
           $i=0;
           echo "$this->keywords<BR>"; 
           while ($i<$this->cnode) {
                 $ptr=$this->child[$i];
                 if ($ptr) {
                    $ptr->shownode();
                 }
                 $i++;
           }
  }

  function findparent($mkey) {
           $i=0;
           if ($this->keywords==$mkey)
              return $this;

          while ($i<$this->cnode) {
                 $ptr=$this->child[$i];
                 if ($ptr) {
                    if ($mt=$ptr->findparent($mkey))
                       break;
                 }  
                 $i++;
           }
           return $mt;
  }

  function nodetree($mkey="\\", $mTitle="Home Page") {
           $this->keywords = $mkey;
           $this->Title=$mTitle;
  }

}

$pp = new nodetree();
$pp1 = new nodetree("0001", "car 1");
$pp2 = new nodetree("0011", "car 2");
$pp3 = new nodetree("0111", "car 3");

//$pp->add_childin($pp3, "0001");
$pp->add_child($pp2);
$pp->add_child($pp1);
$pp1->add_child($pp3);
echo $pp1->cnode;
echo "-----------------------------------<BR>";
$pp->shownode();

echo "-----------------------------------<BR>";

?>

Thi idea is create a tree using keywords but doesn't work... please anyone find a problem o get an idea!!

greetings saul