Online PHP editor | output for 6M0HJ

<?php interface i { protected function getVar(); public function __construct(); } class a implements i { protected $var; public function __construct() { $this->var = 'no value'; } public function getVar() { return $this->var; } } class b extends a { public function __construct($var = 'no value') { $this->var = $var; } } $a = new a(); echo $a->getVar()."\n"; $b = new b('a value'); echo $b->getVar()."\n";