Re: [PHP] Object Undefinded index

[Allex]

In my view, to keep the object oriented approach cleaner you should use 
another class for describing your item, like:

class Item {

  var $_product_id;
  var $_quantity;
  function Item($productId, $quantity) {
    $this->_product_id = $productId;
    $this->_quantity = $quantity;
  }
  function getProductID() {
    return $this->_product_id;
  }
  function getQuantity() {
    return $this->_quantity;
  }
}

Then your Cart class should be defined as follows:

class Cart {

  var $_items;

  function Cart() {
    $this->_items = array();
  }
  function addItem($item) {
    $this->_items[] = $item;
  }
  function getItem($id) {
    return $this->_items[$id];
  }
}

To add a new item to the cart first create the new item by calling the 
items constructor and then call addItem method of the Cart class(object):

$MyCart = new Cart();
...
$newItem = new Item("10", 1);
$MyCart->addItem($newItem);
To iterate items in a Cart you may do something like that:

foreach ($MyCart->getItems as $Item) {
  echo($Item->getProductId(), $Item->getQuantity);
}
Allex

Steve Turner wrote:
I am just learning to use objects. I am messing around with a shopping cart
object, but am having confusing problems. I am getting an undefined index
error when trying to assign a key value pair to an array variable within an
object. I am confused becuase I believe this is how you assign array
variables outside an object. It acts like the variable is undefined. Thanks
for the help.
Steve Turner

//--------------------------------------------------
class Cart
{
    var $items;  // Items in shopping cart
    // Add $quantity articles of $product_id to the cart

    function add_item ($product_id, $quantity = 1)
    {
        $this->items[$product_id] += $quantity;
    }
    // Take $quantity articles of $product_id out of the cart

    function remove_item ($product_id, $quantity)
    {
        if ($this->items[$product_id] > $quantity)
  {
            $this->items[$product_id] -= $quantity;
            return true;
        }
  else
  {
            return false;
        }
    }
}
//I am interacting with the object with the following code
$cart = new Cart;
$cart->add_item("10", 1);
foreach ($cart as $product_id => $quantity)
{
echo $product_id . "<br>" . $quantity;
}
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php