PHP Shopping Cart Category

<?PHP/** * Shopping cart category*/Session_Start();classcart{Private Static $ins=NULL; Private $items=Array(); protected function__construct () {}//Get Instance    protected Static functionGetins () {if(! (Self::$insinstanceof Self)) { Self::$ins=NewSelf (); }        returnSelf::$ins; }    //Put the cart's singleton into session     Public Static functionGetcart () {if(!isset($_session[' cart ']) || ! ($_session[' Cart '] (instanceof Self)) {$_session[' cart '] = self::Getins (); }        return  $_session[' Cart ']; }    /** * Add Item * @param int $id Item ID * @param string $name product name * @param float $price commodity price * @param int $num quantity of goods purchased*/     Public functionAddItem ($id,$name,$price,$num=1){        #The item is already in the shopping, add its quantity        if($this->hasitem ($id)){            $this->inccartnum ($id,$num); return true; }        $this->items[$id] =Array(            ' id ' =$id, ' name ' = =$name, ' price ' =$price, ' num ' =$num        ); return true; }    /** * Empty cart*/     Public functionClearcart () {$this->items =Array(); }    /** * Determine if a product exists * @param int $id Product ID*/     Public functionHasitem ($id){        return array_key_exists($id,$this-items); }    /** * Modify the number of items in your cart * @param int $id commodity ID * @param int $num The number of changes to a product, that is, to change the quantity of an item directly to $num*/     Public functionModifycartnum ($id,$num=1){        if(!$this->hasitem ($id)){            return false; }        $this->items[$id[' num '] =$num; }    /** * 1 increase in product volume*/     Public functionInccartnum ($id,$num=1){        if($this->hasitem ($id)){            $this->items[$id[' num '] + =$num; }    }    /** * 1 reduction in product volume*/     Public functionDeccartnum ($id,$num=1){        if($this->hasitem ($id)){            $this->items[$id[' num ']-=$num; }        if($this->items[$id[' Num '] < 1){            $this->deletecartgoods ($id); }    }    /** * Delete items*/     Public functionDeletecartgoods ($id){        return unset($this->items[$id]); }    /** * Check the number of shopping cart product categories*/     Public functionGetCount () {return Count($this-items); }    /** * Check the number of shopping cart items*/     Public functionGetgoodsnum () {if($this->getcount = = 0)return0; $sum= 0; foreach($this->items as $item){            $sum+=$item[' Num ']; }        return $sum; }    /** * Check the total amount of shopping cart items*/     Public functiongetgoodspricetotal () {if($this->getcount = = 0)return0; $price= 0.0; foreach($this->items as $item){            $price+=$item[' Num ']*$item[' Price ']; }        return $price; }    /** * Return all items in cart*/     Public functiongetcartlist () {if($this->getcount = = 0)return false; return $this-items; }}?>

PHP Shopping Cart Category