Newbie - treestructure
| From: | Johan Evers Petersen | Date: | Thu, 19 Apr 2001 21:59:36 +0000 |
| Subject: | Newbie - treestructure | ||
| Groups: | php.general | ||
| Request: | Send a blank email to php-general+get-49435@lists.php.net to get a copy of this message | ||
I'm Newbie - sorry if this is the wrong list!
I'm trying to print this treestructure I've made, but it doesn't seem to print more
than the first level. The
subtree array of the children is empty, perhaps because I do not
use the correct reference passing?
Thank you for helping me out.
This is the code:
<?php require('database.php'); // $databaseis defined here $database = new db(); class
TreeNode
{
var $data; //Database object reference
var $id; //Unique ID from the database
var $subtree; //Array of treenodes that are the children of $currentNode
var $level; //Level in the tree. The toplevel = 0 function TreeNode($id, $data, $level)
//Constructor
{
$this->id = $id;
$this->data = $data;
$this->level = $level;
$this->subtree = array();
} function add($currentNode)
{
//This function is used to add a TreeNode, $currentNode to the subtree
print "parent: ". $this->id ." New node: ". $currentNode->id
."<br>";
$this->subtree[] = $currentNode;
} function output()
{
for ($i=0;$i<count($this->subtree);$i++)
{
$tree =& $this->subtree[$i];
if (is_object($tree))
print "ID: ".$tree->id."<BR>";
print "Count: ".count($tree->subtree)."<BR>";
$tree->output();
} /* foreach ($this->subtree as $tree) //Skal være en while løkke, da $tree->subtree er
tomt.
{
if (is_object($tree))
print "ID: ".$tree->id."<BR>";
$tree->output();
}
*/
}
} //Initialize
$treetop = new TreeNode(0, 0, -1); // You have to have a start position
$nodehash = array(); // This is only used to find the parents //Make the query
$sql = "SELECT * FROM page_table WHERE visible=1 ORDER BY id, title";
$query = new query($database, $sql); while ($obj = $query->getobj())
{
if($obj->parent_id > 0){ //If the node is not on the toplevel
$parent =& $nodehash["id_$obj->parent_id"]; //Finds the parent in the $nodehash
}
else
{
$parent =& $treetop; //If the node is on the toplevel then the parent is $treetop
}
$level = $parent->level + 1; //The tree level of $currentNode is of course one more than the
$parent (level
is not stored in db) //when we have found the level of $currentnode we are ready to construct the
$currentNode using the parameters
from the database and the $level
$currentNode = new TreeNode($obj->id, $obj, $level);
$nodehash["id_$obj->id"] = $currentNode; //Insert the $currentNode into the $nodehash
so we can find it again
if it has any children
$parent->add($currentNode); //Use the add function of the $parent to put $currentNode into
$parent's subtree
} //Something has to be printed out...
$treetop->output();
?>