how is $cart registered?

[seanpaulcail]

coming from a page that shows book details, A user clicks "add to cart" and the following url (CHAPTER25d/show_cart.php?new=0672317842) leads to the next page with the following information

<?
  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);

  }

so how is cart registered and why is it incrmented by one? And what about the parameter passed to "new" in the url?

I need a good explanation of what's happening here, otherwie I am operating without unerstanding exactly what I am doing.

Thanks

[rIkLuNd]

first it checks if $new is set. then it checks if a cart have been registered, otherwise it will register one. then it checks if there already is one or more objects of this type ($new) in the cart, and if there is, the amount will be incremented by one. if no object of this type exists, then it will add the object $new to the cart.

Did it help?

[seanpaulcail]

I was getting confused but you have cleared things up.

I've reading lot's of PHP but when it come down to the true functionality books seldom give the answers.

Thanks again😃

[rIkLuNd]

Glad I could be of help!