function cart_subtotal() { $subtotal = 0; $cart = cart_get_items(); foreach ($cart as $item) { $subtotal += $item['unit_price'] * $item['quantity']; } return $subtotal; }
$cart = cart_get_items(); break; case 'add': $product_id = $_GET['product_id']; $quantity = $_GET['quantity']; $product = get_product($product_id); // validate the quantity entry if (empty($quantity)) { display_error('You must enter a quantity.'); } elseif (!is_valid_number($quantity, 1)) { display_error('Quantity must be 1 or more.'); } cart_add_item($product_id, $quantity); $cart = cart_get_items(); break; case 'update': $items = $_POST['items']; foreach ($items as $product_id => $quantity) { if ($quantity == 0) { cart_remove_item($product_id); } else { cart_update_item($product_id, $quantity); } } $cart = cart_get_items(); break; default: add_error("Unknown cart action: " . $action); break; } include './cart_view.php';