Binary tree using php

PHP
3

Here’s a version without the recursive add – so it would use way less memory when adding large data sets as it’s not making endless copies of the data being added to the tree.


<?php
class nodeElement {
	public
		$data,
		$prev=false,
		$next=false;

	public function __construct($data) {
		$this->data=$data;
	}

	public function show() {
		if ($this->prev) $this->prev->show();
		echo $this->data,'<br />';
		if ($this->next) $this->next->show();
	}
}

class nodeTree {
	public
		$first=false;

	public function add($data) {
		if ($this->first) {
			$current=$this->first;
			while (true) {
				if (strnatcasecmp($current->data,$data)<0) {
					if ($current->next) {
						$current=$current->next;
					} else {
						$current->next=new nodeElement($data);
						break;
					}
				} else {
					if ($current->prev) {
						$current=$current->prev;
					} else {
						$current->prev=new nodeElement($data);
						break;
					}
				}
			}
		} else {
			$this->first=new nodeElement($data);
		}
	}

	public function show() {
		if ($this->first) {
			$this->first->show();
		}
	}

}

$test=new nodeTree();
$test->add('bravo');
$test->add('charlie');
$test->add('echo');
$test->add('alpha');
$test->add('delta');
$test->show();

?>