Online PHP editor | output for qhjl5

<?php class Foo { public $id; } class Foo2 { public $id; public function __construct($id) { $this->id = $id; } } class Foo3 { protected $id; public function __construct($id) { $this->id = $id; } public function getId() { return $this->id; } } class Foo4 { protected $id; public function __construct($id) { $this->id = $id; } public function __get($key) { return $this->id; } } $data = new Foo; $data->id = 10; echo $data->id; $data2 = new Foo2(10); echo $data2->id; $data3 = new Foo3(10); echo $data3->getId(); $data4 = new Foo4(10); echo $data4->id;