Class and variable issue please help

[tamagraphics]

I am having an issue getting a variable to carry over into a class for a shopping cart system I am tring to work on. 

 

I have a variable called $cartid with is develped and stored into a cookie as a session variable.

 

I then call for the start of the class called cart

 

When i run the function called additem($product, $quantity) which is located inside of the class cart I cannot seem to have access to the variable $cartid.  If you look at the first function of the script i have it assigning

 

$this->cartid = $cartid;

 

Shouldn't this assign the session variable to the $this->cartid inside the class???

 

 

Here is the code below...  hope someone can help...

 

if (!isset($_COOKIE['cartid'])) {

//  If no cookie exists create a new one with a rand integer that is unique and md5 encrpyted for security

$cartid = md5(uniqid(rand()));
setcookie("cartid", $cartid, time() + 14400);  //  Set to expire in 1 minute for test purpose - set to 4 hours when live = 14400  3600 is 1 hour


} else {

//  If cookie does exist then grab the id number from the cookie for user data
$cartid = $_COOKIE['cartid'];

}


//  Start of shopping Cart class

class cart {



var $host = "hostname";
var $user = "username";
var $password = "password";
var $data = "databasename";

var $invtable = "inventory";	        	//  Name of the table holding the products information
var $carttable = "orders";			//  Name of the table holding the information for the shopping carts


//  Database connection function

function cart($cartid) {


$this->dblink = mysql_connect($this->host, $this->user, $this->password);
mysql_select_db($this->data, $this->dblink);
$this->cartid = $cartid;


}




//  Start of function to add to the shopping cart

function additem($product, $quantity) {

echo $cartid;
echo $this->cartid;

$qty = $this->checkitem($product);
// echo $this->cartid;

if ($qty == 0) {

	$query = "insert into " . $this->carttable . " (session, product, quantity, id) values ('" . $this->cartid . "', '$product', '$quantity', '') ";
	mysql_query($query, $this->dblink);

} else {

	$quantity += $qty;
	$query = "update " . $this->carttable . " set quantity = '$quantity' where (session = '" . $this->cartid . "' and product = '$product') ";
	mysql_query($query, $this->dblink);

}
return true;

}



function checkitem($product) {

echo $cartid;
echo $this->cartid;

$query = "select quantity from orders where (session = '" . $this->cartid . "' and product = '$product') ";
$result = mysql_query($query, $this->dblink);

if (!$result) {

	return 0;

}

$numrows = mysql_numrows($result);

// echo $numrows;

if ($numrows !=0) {

	$row = mysql_fetch_object($result);
	return $row->quantity;

}

}

 

Thank you.