Practical php shopping cart program_PHP tutorial

Practical PHP Tutorial Shopping Cart Program
I have used one before and it felt good, but I also feel good after reading this one, so I will introduce it to friends who need it for reference.

//Calling instance
require_once 'cart.class.php';
session_start();
if(!isset($_SESSION[ 'cart'])) {
$_SESSION['cart'] = new Cart;
}
$cart =& $_SESSION['cart'];

if( ($ _SERVER['REQUEST_METHOD']=="POST")&&($_POST['action']=='add') ){
$p = $_POST['p'];
$items = $ cart->add($p);
}
if( ($_GET['action']=='remove')&&($_GET['key']!="") ) {
$items = $cart->remove($_GET['key']);
}

if( ($_SERVER['REQUEST_METHOD']=="POST")&&($ _POST['action']=='modi') ){
$key = $_POST['key'];
$value = $_POST['value'];
for($i= 0;$i $items = $cart->modi($key[$i],$value[$i]);
}
}

$items = $cart->getCart();
//Print
echo "

";
setlocale(LC_MONETARY, 'it_IT') ;
foreach($items as $item){
echo "";
echo "

ID: ".$item['ID'].""; echo "	Product: ".$item['name']; echo "	Unit price: ".$item['price']; echo "	"; $sum = $item['count']*$item['price']; echo " echo "	"; } echo ""; echo "
"; echo "

";

?> ;

---

ID:Product name:
Unit price:
Quantity:

/**
 * Cart
 *
 * 购物车类
 *
 * @author  doodoo
 * @package     Cart
 * @category    Cart
 * @license     PHP License
 * @access      public
 * @version     $Revision: 1.10 $
 */
Class Cart{

var $cart;
var $totalCount; //Total quantity of goods
var $totalPrices; //Total amount of goods

/**
* Cart Constructor
*
* Constructor of the class to keep the shopping cart in a stable initialization state
*
* @static
* @access public
* @return void No return value
* @param void No parameter
*/
function Cart(){
$ this->totalCount = 0;
$this->totalPrice = 0;
$this->cart = array();
}

// }}}
// {{{ add($item)

/**
* Add products to the current shopping cart
*
* @access public
* @param array $item product information (one-dimensional array: array(product ID, product name, product unit price, product quantity ))
* @return array Returns the array of items in the current shopping cart
*/
function add($item){
if(!is_array($item)||is_null($item)) return $this->cart;
if(!is_numeric(end($item))||(!is_numeric(prev($item)))) {
echo "Price and quantity must be numbers";
return $this->cart ;
}
reset($item); //This sentence is necessary because the above judgment has moved the array index
$key = current($item);
if($ key=="") return $this->cart;
if($this->_isExists($key)){ //Does the product already exist?
$this->cart[$key]['count'] = end($item);
return $this->cart;
}

$this-> ;cart[$key]['ID'] = $key;
$this->cart[$key]['name'] = next($item);
$this->cart[ $key]['price'] = next($item);
$this->cart[$key]['count'] = next($item);

return $this- >cart;
}

// }}}
// {{{ add($item)

/**
* Remove some or all items from the current shopping cart
* When $key=="", clear the current shopping cart
* When $key!=""&&$count=="" When , pick out all the products with the product ID number $key from the current shopping cart
* When $key!=""&&$count!="" , pick out $count items from the current shopping cart Product with product ID number $key
*
* @access public
* @param string $key product ID
* @return mixed Returns true or false or an array of products in the current shopping cart
*/
function remove($key="",$count=""){
if($key=="") {
$this->cart = array();
return true;
}
if(!array_key_exists($key,$this->cart)) return false;
if($count==""){ //Remove this category of goods
unset( $this->cart[$key]);
}else{ //Remove $count items
$this->cart[$key]['count'] -= $count;
if($this->cart[$key]['count']<=0) unset($this->cart[$key]);
}
return $this-> ;cart;
}

// }}}
// {{{ modi($key,$value)

/**
* Modify the quantity of the product with product ID $key in the shopping cart to $value
*
* @access public
* @param string $key product ID
* @param int $ value item quantity
* @return array Returns the array of items in the current shopping cart;
*/
function modi($key,$value){
if(!$this->_isExists($key)) return $this->cart(); //This product does not exist, return directly
if($value<=0){ // value is too small, delete all
unset($this->cart[$key]);
return $this->cart;
}
$this->cart[$key]['count'] = $value;
return $this->cart;
}

/**
* Returns an array of items in the current shopping cart
*
* @access public
* @return array Returns an array of items in the current shopping cart;
*/
function getCart(){
return $this->cart;
}

// }}}
// {{{ _isExists($key)

/**
* Determine whether there is a product with the product ID number $key in the current shopping cart
*
* @access private
* @param string $key product ID
* @return bool true or false;
*/
function _isExists($key)
{
if(isset($this->cart[$key])&&!empty($ this->cart[$key])&&array_key_exists($key,$this->cart))
return true;
return false;
}

// }}}
// {{{ isEmpty()

    /**
* Determine whether the current shopping cart is empty, that is, there are no products
*
* @access public
* @return bool true or false;
*/
 function isEmpty(){
  return !count($this->cart);
 }

 // }}}
    // {{{ _stat()

    /**
* Obtain some statistical information
*
* @access private
* @return bool true or false;
*/
 function _stat(){
  if($this->isEmpty()) return false;
  foreach($this->cart as $item){
   $this->totalCount   = @end($item);
   $this->totalPrices  = @prev($item);
  }
  return true;
 }

 // }}}
    // {{{ totalPrices()

    /**
* Get the total amount of all items in the current shopping cart
*
* @access public
* @return float Return amount;
*/
 function totalPrices(){
  if($this->_stat())
   return $this->totalPrices;
 return 0;
 }

 // }}}
    // {{{ isEmpty()

    /**
* Get the total quantity of all items in the current shopping cart and
*
* @access public
* @return int ;
*/
 function totalCount(){
  if($this->_stat())
   return $this->totalCount; 
 return 0;
 }

}//End Class Cart
?>