How to add custom class to last post In A loop wordpress

<?php
function last_post_class($classes){
global $wp_query;
if(($wp_query->current_post+1) == $wp_query->post_count) $classes[] = 'Your Class Name';
return $classes;
}
add_filter('post_class', 'last_post_class');
?>
After this you display your class name in your last Post.