<!-- Collection of code snippets by Arne Vajhøj -->
<!-- posted to eksperten.dk, usenet and other places (2002-now) -->
<?php
abstract class Animal {
    private $name;
    public function __construct($name) {
        $this->name = $name;
    }
    public abstract function sound();
    public function says() {
        echo $this->name . ' siger ' . $this->sound() . "\r\n";
    }
}

class Dog extends Animal {
    public function sound() {
        return 'Vuf';
    }
}

class Cat extends Animal {
    public function sound() {
        return 'Mjav';
    }
}

$pets = array(new Dog('King'), new Cat('Sorte misser'));
foreach($pets as $pet) {
    $pet->says();
}
?>