if (((isset($_SESSION['id_usertype'])) AND ($_SESSION['id_usertype']==1)) OR ((isset($_COOKIE['id_user']) AND ($_SESSION['id_usertype']==1)))) {

// stampa della roba (Non reindirizza)

} else {
    if ((isset($_SESSION['id_usertype'])) AND ($_SESSION['id_usertype']==4) AND (isset($_SESSION['id_student']))) {
        header('Location: student-page.php');
    } else
    {
        if ((isset($_SESSION['id_usertype'])) AND ($_SESSION['id_usertype']==2)) {
            header('Location: projects.php');
        }
        else {
            header('Location: login.php');
            //echo("stop");
            //echo("id_usertype: ".$_SESSION['id_usertype']);
        }
    }

}