class Check {
    public function mty() {
        global $required;
        global $field;

        foreach($required as $field) {
            if (empty($_POST[$field])) {
                //Code...
            } else {
                echo "Good";
            }
        }
    }
}

$check = new Check;

//Gets names of inputs
$required = array('name', 'price', 'id');

if(isset($_POST['submit'])) {
    $check->mty();
}