$new ???

[seanpaulcail]

ok . . . oe page one a book and its detailed are displayed then there is option to add the book to the cart with the following code:

display_button("show_cart.php?new=$isbn", "add-to-cart", "Add ".$book["title"]." To My Shopping Cart");

The book is added which takes us to "show_cartphp with $isbn passed as a parameter.

then this code is on the show_cart.php page

<?
include ('book_sc_fns.php');
// The shopping cart needs sessions, so start one
session_start();

if($new)
{
//new item selected
if(!session_is_registered("cart"))
{
$cart = array();
session_register("cart");
$items = 0;
session_register("items");
$total_price = "0.00";

session_register("total_price");
}
if($cart[$new])
$cart[$new]++;
else
$cart[$new] = 1;
$total_price = calculate_price($cart);
$items = calculate_items($cart);

}

My question is: "isn't $new replaced by the $isbn?

or does new still remain?

I guess $new still remains with holding the $isbn parameter.

But then the second if statment on the second page changes $new by incrementing it or changing it to 1.

What happened to the $isbn.

utterly confused.

Thanks

[sfullman]

OK, here's the basics:
$new is simply a way of passing a book number (isbn). This is a STRING.

It's also a KEY, or Name, in the array CART. This key has a VALUE, such as one or two, etc., and it's a NUMBER.

so you don't really have to say:

if(!$cart[$new]){

$cart[$new]++;
}else{
$cart[$new] = 1;
}

You can just go:
$cart[$new]++;

...because if $cart[$new] doesn't have a quantity, it will after the ++, namely a quantity of 1.

MAIN THING to understand is that ISBN (string) is the KEY, and Quantity is a number and it's a VALUE of that key.