Online PHP editor | output for ig5Dc

<?php namespace forum; class Base { public function __construct($a, $b) { } public function sayHello() { echo 'Hello '; } } class SayWorld extends Base { public function __construct($a, $b, $c = 1) { parent ::__construct($a, $b); echo $c . " "; } public function sayHello($a = null) { parent ::sayHello(); echo 'World!'; } } class MyHelloWorld extends SayWorld { } $o = new MyHelloWorld(2, 3); $o -> sayHello(1);