27.10. How to find the user name in a module

<?php
if (!isset($mainfile)) {include("mainfile.php"); }
include ("header.php");
if(!is_array($user)) {
  $user_get = base64_decode($user);
  $user_get = explode(":", $user_get);
  $user_name = "$user_get[1]";
} else {
  $user_name = "$user[1]";
}
if($user_name == "") {$user_name="Anonymous";}
echo "Welcome, $user_name";
include ("footer.php");
?>