PHP教程：php树型类实例

<?php
class tree
{
    var $data = array();
    var $child = array(-1=>array());
    var $layer = array(-1=>-1);
    var $parent = array();
    var $num = array();
 
    function setnode($id, $parent, $value,$num=0)
    {
        $parent = $parent ? $parent : 0;
 
        $this->data[$id]  = $value;
        $this->num[$id]      = $num;
        if (!isset($this->child[$id])) $this->child[$id] = array();
        $this->child[$parent][] = $id;
        $this->parent[$id]  = $parent;
 
        if (!isset($this->layer[$parent]) && $parent == 0)
        {
           $this->layer[$id] = 0;
        }
        else
        {
            $this->layer[$id] = $this->layer[$parent] + 1;
        }
    }
 
    function getlist(&$tree, $root= 0)
    {
        foreach ($this->child[$root] as $key=>$id)
        {
            $tree[] = $id;
            if($this->child[$id]) $this->getlist($tree, $id);
        }
    }
 
    function getvalue($id)
    {
   if($this->layer[$id]==0)
   {
    return $this->data[$id];
   }
   else
   {
    return $leftmar.$this->data[$id];
   }
    }
 
    function getnum($id)
    {
   return $this->num[$id];
    }
 
    function getbitvalue($id)
    {
   return $this->data[$id];
    }
 
    function getlayer($id, $space = false)
    {
        return $space ? str_repeat($space, $this->layer[$id]) : $this->layer[$id];
    }
 
    function getparent($id)
    {
        return $this->parent[$id];
    }
 
    function getparents($id)
    {
        while ($this->parent[$id] != -1)
        {
            $id = $parent[$this->layer[$id]] = $this->parent[$id];
        }
 
        ksort($parent);
        reset($parent);
 
        return $parent;
    }
 
    function getchild($id)
    {
        return $this->child[$id];
    }
 
    function getchilds($id = 0)
    {
        $child = array($id);
        $this->getlist($child, $id);
 
        return $child;
    }
 
    function printdata()
    {
        return $this->layer;
    }
}
?>