Online PHP editor | refs for PBg0b

<?php class Database { private static $database; private function __construct() { // Nothing } public static function getInstance() { if (!self::$database) { self::$database = new Database(); } return self::$database; } } class BasicMath { public function getString($string) { return $string; } public static function add($number1, $number2) { $this->getString('hEllo'); return $number1 + $number2; } } var_dump(BasicMath::add(1, 2));