<?php
class ShoppingCart {
	private $items = array();
	
	function addToCart($item_id) {
		if (!empty($this->items[$item_id]))	{
			//we already have a value, so add 1
            $this->items[$item_id] = $this->items[$item_id] + 1;
		} else {
			//no value, so initialize
            $this->items[$item_id] = 1;
		}
	}
	
	function getCart() {
		return $this->items;
	}
}
?>