xml array to xml

xml_array_to_xml.php

<?php

function createXml($posts, $format = null)
{
    /* output in necessary format */
    if ($format == 'json') {
        header('Content-type: application/json');
        echo json_encode(array('posts' => $posts));
    } else {
        header('Content-type: text/xml');
        echo '<posts>';
        foreach ($posts as $index => $post) {
            if (is_array($post)) {
                foreach ($post as $key => $value) {
                    echo '<', $key, '>';
                    if (is_array($value)) {
                        foreach ($value as $tag => $val) {
                            echo '<', $tag, '>', htmlentities($val), '</', $tag, '>';
                        }
                    }
                    echo '</', $key, '>';
                }
            }
        }
        echo '</posts>';
    }
}