Convert PHP array to xml

<?php

/**
 * Modified v2 http://stackoverflow.com/a/5965940/1113356, Answer
 */

header('Content-Type: text/xml');

$student_info = array(
    0 => array(
        'id'       =>  '001',
        'name'     =>  'Mifas',
        'subjects' => array('English','Maths','IT')
    ),
    1 => array(
        'id'    =>  '002',
        'name'  =>  'Ijas',
        'subjects'  => array('Science','History','Social')
    )
);

// creating object of SimpleXMLElement
$xml_student_info = new SimpleXMLElement("<?xml version=\"1.0\"?><student_info></student_info>");
array_to_xml($student_info,$xml_student_info);          // function call to convert array to xml
print $xml_student_info->asXML();               //saving generated xml file


// function defination to convert array to xml
function array_to_xml($student_info, &$xml_student_info) {
    foreach($student_info as $key => $value) {
    $key = is_numeric($key) ? "item$key" : $key;
        (is_array($value))
        ? array_to_xml($value, $xml_student_info->addChild("$key"))
        : $xml_student_info->addChild("$key","$value");
    }
}

?>