Getters and Setters in PHP OOP

<?php 

class Product
{
    private $id;
    private $name;
    private $price;
    private $quantity;

    public function getId()
    {
        return $this->id;
    }

    public function setId($id)
    {
        $this->id = $id;
    }

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

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

    public function getPrice()
    {
        return $this->price;
    }

    public function setPrice($price)
    {
        $this->price = $price;
    }

    public function getQuantity()
    {
        return $this->quantity;
    }

    public function setQuantity($quantity)
    {
        $this->quantity = $quantity;
    }
}

$product = new Product();
$product->setId('p01');
$product->setName('name 1');
$product->setPrice(4.5);
$product->setQuantity(2);

echo 'Product Info';
echo '<br>id: ' . $product->getId();
echo '<br>name: ' . $product->getName();
echo '<br>price: ' . $product->getPrice();
echo '<br>quantity: ' . $product->getQuantity();
echo '<br>total: ' . ($product->getPrice() * $product->getQuantity());

?>

Output

Product Info
id: p01
name: name 1
price: 4.5
quantity: 2
total: 9