php 购物车功能

<?php
session_start();

// 添加商品到购物车
function addToCart($productId, $quantity) {
    if (isset($_SESSION['cart'])) {
        $cart = $_SESSION['cart'];
    } else {
        $cart = [];
    }
    if (array_key_exists($productId, $cart)) {
        $cart[$productId]['quantity'] += $quantity;
    } else {
        $cart[$productId] = ['quantity' => $quantity];
    }
    $_SESSION['cart'] = $cart;
}

// 显示购物车内容
function showCart() {
    if (isset($_SESSION['cart'])) {
        $cart = $_SESSION['cart'];
        foreach ($cart as $productId => $item) {
            echo "Product ID: $productId, Quantity: " . $item['quantity'] . "<br>";
        }
    } else {
        echo "Your cart is empty.";
    }
}

// 示例：添加商品到购物车
addToCart(1, 2);
addToCart(2, 1);

// 显示购物车内容
showCart();
?>