// 购物车类

class Cart {

    private $items = [];

    public function addItem(Product $product) {

        $this->items[] = $product;

    }

    public function getTotal() {

        $total = 0;

        foreach ($this->items as $item) {

            $total += $item->getPrice() * $item->getQuantity();

        }

        return $total;

    }

}

// 产品类

class Product {

    private $name;

    private $price;

    private $quantity;

    public function __construct($name, $price, $quantity) {

        $this->name = $name;

        $this->price = $price;

        $this->quantity = $quantity;

    }

    public function getName() {

        return $this->name;

    }

    public function getPrice() {

        return $this->price;

    }

    public function getQuantity() {

        return $this->quantity;

    }

}

// 用例

$cart = new Cart();

$cart->addItem(new Product('苹果', 10, 2));

$cart->addItem(new Product('香蕉', 8, 3));

echo "购物车总价：" . $cart->getTotal(); // 输出 44