3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $id = 79891959856; $len = strlen($id); $input = "FDFDSFD"; $final_len = 6+strlen($input)-$len; echo $final_len.">>".str_pad($input, $final_len, "0", STR_PAD_RIGHT).$id;
Output for 4.3.0 - 7.1.0
2>>FDFDSFD79891959856