<?php
    class Loadxml{
        public function __construct($xmlFile){
            $this->xmlFile = simplexml_load_file($xmlFile);

            foreach ($this->xmlFile->song as $song){
                $this->sort[] = $song;
            }
            // sort the array
            usort($this->sort, function($a, $b){ return $a->category - $b->category; });
        }

        public function display(){
            echo'<table border="1">
                    <tr>
                        <td>Title</td>
                        <td>Artist</td>
                        <td>Duration</td>
                        <td>Release</td>
                        <td>Category</td>';
            foreach($this->sort as $new){
                    echo'<tr><td>' . $new->title . '</td>
                    <td>' . $new->artist . '</td>
                    <td>' . $new->duration . '</td>
                    <td>' . $new->release . '</td>
                    <td>' . $new->category . '</td>';
            }
            echo'</tr></table>';
        }
    }
?>