Nested comments code not working - php

Question

I'm trying to implement code for nested commenting which I found at http://www.jongales.com/blog/2009/01/27/php-class-for-threaded-comments/.
But for some reason I can't get it to work. My result is
"Parent Child Child Third level Second Parent Second Child" in one row
without any nesting. What am I doing wrong? Is there maybe a setting or extension which I have to enable for this to work? Thanks in advance!
Here's the exact code I'm using:
<?php
class Threaded_comments
{
public $parents = array();
public $children = array();
/**
* #param array $comments
*/
function __construct($comments)
{
foreach ($comments as $comment)
{
if ($comment['parent_id'] === NULL)
{
$this->parents[$comment['id']][] = $comment;
}
else
{
$this->children[$comment['parent_id']][] = $comment;
}
}
}
/**
* #param array $comment
* #param int $depth
*/
private function format_comment($comment, $depth)
{
for ($depth; $depth > 0; $depth--)
{
echo "\t";
}
echo $comment['text'];
echo "\n";
}
/**
* #param array $comment
* #param int $depth
*/
private function print_parent($comment, $depth = 0)
{
foreach ($comment as $c)
{
$this->format_comment($c, $depth);
if (isset($this->children[$c['id']]))
{
$this->print_parent($this->children[$c['id']], $depth + 1);
}
}
}
public function print_comments()
{
foreach ($this->parents as $c)
{
$this->print_parent($c);
}
}
}
$comments = array( array('id'=>1, 'parent_id'=>NULL, 'text'=>'Parent'),
array('id'=>2, 'parent_id'=>1, 'text'=>'Child'),
array('id'=>3, 'parent_id'=>2, 'text'=>'Child Third level'),
array('id'=>4, 'parent_id'=>NULL, 'text'=>'Second Parent'),
array('id'=>5, 'parent_id'=>4, 'text'=>'Second Child')
);
$threaded_comments = new Threaded_comments($comments);
$threaded_comments->print_comments();
?>

Answer 1

I think you will only see the formating in a console, not if use it in a web page. if you want it in a web page you must replace the \n and \t in the following function with <br/> and respectively.
/**
* #param array $comment
* #param int $depth
*/
private function format_comment($comment, $depth)
{
for ($depth; $depth > 0; $depth--)
{
echo "\t";
}
echo $comment['text'];
echo "\n";
}
should become :
/**
* #param array $comment
* #param int $depth
*/
private function format_comment($comment, $depth)
{
for ($depth; $depth > 0; $depth--)
{
echo " ";
}
echo $comment['text'];
echo "<br />";
}