PHP use session to achieve the simplest way to implement the shopping cart class

Class Cart
{
/**
* Function Name: AddItem
* Function function: Add product
* Input parameters: $data-------------product Array
* Function return value: None
* Other Description: Because the data is recorded in the session, so do not return
*/
function AddItem ($data) {
Global $config _kezhi;
if (Is_array ($data) &&!empty ($data)) {
foreach ($data as $key => $val) {
Add quantity and price if goods exist
if ($this->_isexists ($key)) {

$_session[' cart ' [$key] ["paddy_count"] + = $val [' Paddy_count '];
$_session[' cart ' [$key] ["market_count"] + = $val [' Market_count '];
$_session[' cart ' [$key] ["goodsnum"] + = Intval ($val [' goodsnum ']);
$arr = $this->getitems ($key);
$_session[' cart ' [$key] ["count"] = = $_session[' cart '] [$key] ["Price"];
/* IF (strlen ($_session[' cart '] [$key] ["Kezhi"]) >0) {//no lettering, add lettering
$_session[' cart ' [$key] ["Eng_price"]=0;
$_session[' cart ' [$key] ["Eng_price"]= (int) $config _kezhi*intval ($arr [' num ']);
}else{
Die ("DD");
$_session[' cart ' [$key] ["Eng_price"]=0;
}*/
echo $arr [' num '];
Die ();

}
Otherwise join directly
Else
{
$_session[' cart ' [$key] = $data [$key];
$_session[' cart ' [$key] [' name '] = $val [' name '];
$_session[' cart ' [$key] ["price"] = $val [' Price '];
$_session[' cart ' [$key] [' count '] = round ($val [' Price ']*intval ($val [' num ']), 2);
$_session[' cart ' [$key] ["num"] = intval ($val [' num ']);
}
}
}
}

/**
* Function Name: _isexists
* Function function: To determine whether this product exists
* Input parameters: $id----------Product ID
* Function return value: BOOL
* Other Notes: 2004-8-19
*/
function _isexists ($id)
{
if (isset ($_session[' cart '] [$id]) &&!empty ($_session[' cart '] [$id]) &&array_key_exists ($id, $_ session[' cart '])
{
return true;
}
Else
{
return false;
}
}

/**
* Function Name: Moditem
* Function Function: Modify the number of goods
* Input parameters: $id--------------Product ID
* Number of $num-------------commodities
* Function return Value: Return value description
* Other Notes: Description
*/
function Moditem ($id, $num)
{
$arr = $this->getitems ($id);
Add quantity and price if goods exist
if ($this->_isexists ($id))
{
$_session[' cart ' [$id] ["goodsnum"] = Intval ($num);
if ($arr [' paddy_price_special '] > "0") {
$_session[' cart ' [$id] ["paddy_count"] = round ($arr [' Paddy_price_special ']*intval ($num), 2);
}elseif ($arr [' Paddy_userprice '] > "0") {
$_session[' cart ' [$id] ["paddy_count"] = round ($arr [' Paddy_userprice ']*intval ($num), 2);
}elseif ($arr [' Paddy_spreadprice '] > "0") {
$_session[' cart ' [$id] ["paddy_count"] = round ($arr [' Paddy_spreadprice ']*intval ($num), 2);
}else{
$_session[' cart ' [$id] ["paddy_count"] = round ($arr [' Paddy_price ']*intval ($num), 2);
}
$_session[' cart ' [$id] ["market_count"] = round ($arr [' Market_price ']*intval ($num), 2);
}
}

/**
* Function Name: Moditem_wanwei
* Function Function: Modify the product wrist circumference
* Input parameters: $id--------------Product ID
* $num-------------Commodity wrist circumference
* Function return Value: Return value description
* Other Notes: Description
*/
function Moditem_wanwei ($id, $wanwei)
{
$arr = $this->getitems ($id);
Add quantity and price if goods exist
if ($this->_isexists ($id))
{
$_session[' cart ' [$id] ["wanwei"] = Intval ($wanwei);

$_session[' cart ' [$id] ["count"] = round ($arr [' Price ']*intval ($num), 2);
}
}

function Moditem_kezhi ($id, $kezhi)
//    {
Global $config _kezhi;
$arr = $this->getitems ($id);
Add quantity and price if goods exist
if ($this->_isexists ($id))
//        {
$_session[' cart ' [$id] ["kezhi"] = $kezhi;
$_session[' cart ' [$id] [' price '] = $arr [' price '] + $config _kezhi;
$_session[' cart ' [$id] [' count '] = round ($_session[' cart '] [$id] [' Price ']*intval ($arr [' num ']], 2);
//        }
//    }


function Moditem_kezhi ($id, $kezhi, $kezhi 1= "", $kezhi 2 = "")
{
Global $config _kezhi;
$arr = $this->getitems ($id);
Add quantity and price if goods exist
Var_dump ($_session[' cart '));
Die ();
if ($this->_isexists ($id))
{
if (strlen ($_session[' cart '] [$id] ["Kezhi"]) = = 0 && strlen ($kezhi)!= 0) {//no lettering, add lettering
$arr [' price '] + = $config _kezhi;
$_session[' cart ' [$id] ["Eng_price"]=0;
$_session[' cart ' [$id] ["Eng_price"]= (int) $config _kezhi*intval ($arr [' num ']);
$_session[' cart ' [$id] ["price"] = $arr [' Price '];
$_session[' cart ' [$id] [' count '] = round ($arr [' Price ']*intval ($arr [' num ']), 2);
$_session[' cart ' [$id] ["kezhi"] = $kezhi;
$_session[' cart ' [$id] ["kezhi1"] = $kezhi 1;
$_session[' cart ' [$id] ["kezhi2"] = $kezhi 2;
$_session[' cart ' [$id] ["count"] = round ($arr [' Price ']*intval ($num), 2);
}elseif (strlen ($_session[' cart '] [$id] ["Kezhi"])!= 0 && strlen ($kezhi) = = 0) {//have lettering, remove lettering
$_session[' cart ' [$id] ["Eng_price"]=0;
$_session[' cart ' [$id] ["Eng_price"]-= (int) $config _kezhi*intval ($arr [' num ']);
$_session[' cart ' [$id] ["Eng_price"]-= $config _kezhi;
$_session[' cart ' [$id] ["price"] = $arr [' Price '];
$_session[' cart ' [$id] [' count '] = round ($arr [' Price ']*intval ($arr [' num ']), 2);
$_session[' cart ' [$id] ["kezhi"] = $kezhi;
$_session[' cart ' [$id] ["kezhi1"] = $kezhi 1;
$_session[' cart ' [$id] ["kezhi2"] = $kezhi 2;
}elseif (strlen ($_session[' cart '] [$id] ["Kezhi"])!= 0 && strlen ($kezhi)!= 0) {//have lettering, change lettering
$_session[' cart ' [$id] [' count '] = round ($arr [' Price ']*intval ($arr [' num ']), 2);
$_session[' cart ' [$id] ["Eng_price"]=0;
$_session[' cart ' [$id] ["Eng_price"]= (int) $config _kezhi*intval ($arr [' num ']);

$_session[' cart ' [$id] ["kezhi"] = $kezhi;
$_session[' cart ' [$id] ["kezhi1"] = $kezhi 1;
$_session[' cart ' [$id] ["kezhi2"] = $kezhi 2;
}
}
}

/**
* Function Name: GetItems
* Function function: Get the product array
* Input Parameters: $id---------------The ID of a product
* Function return Value: Array
* Other Notes: 2004-8-19
*/
function GetItems ($id =null)
{
if (isset ($_session[' cart '))
{
if ($id ==null)
{
Print_r ($_session[' cart '); exit;
return $_session[' cart '];
}
Else
{
return $_session[' cart ' [$id];
}
}
}

   /**
    *   function name:   emptyitem
    *    function:   Delete product
    *   input parameters:   $id-----------Commodity ID
& nbsp;   *   function return value: BOOL
    *   Other description:   2004-8-19
    */
    function Emptyitem ($id =null)
    {
         if ($id ==null)
        {
             unset ($_session[' cart '));
       }
        Else
        {
             unset ($_session[' cart '] [$id]);
       }
   }

/**
* Function Name: sum
* Function Function: Statistic Total Price
* Input Parameters: None
* Function return value: int
* Other Notes: 2004-8-19
*/
function sum ()
{
$total = 0;
if (isset ($_session[' cart ')) &&!empty ($_session[' cart '))
{
foreach ($_session[' cart '] as $key => $val)
{
$total + + $val [' count '];
}
}
return $total;
}
}