Abstract Classes in PHP OOP

<?php

abstract class Animal
{
    protected $name;

    public function getName()
    {
        return $this->name;
    }

    public function setName($name)
    {
        $this->name = $name;
    }

    abstract public function sound();
}

class Cat extends Animal
{
    public function __construct($name)
    {
        $this->name = $name;
    }

    public function sound()
    {
        echo $this->name . ' sound meow';
    }
}

$cat = new Cat('Cat 1');
$cat->sound();

?>

Output

Cat 1 sound meow