fala galera estou com um script de carrinho de compras, mas é o seguinte qdo tento atualizar a qtd de itens ele zera todo o carrinho podem me dar uma força:

PHP [/tr][tr]<?

Script para carrinho.php

session_start();

Adiciona itens ao carrino

if($new)

{

if(!session_is_registered("cart"))

{

$cart = array();

session_register("cart");

$items = 0;

session_register("items");

}

 

if($cart[$new])

$cart[$new]++;

else

$cart[$new] = 1;

$items = calculate_items($cart);

}

Deveria atualizar o carrinho

if($save)

{

foreach ($cart as $isbn => $qty)

{

if($$isbn=="0")

unset($cart[$isbn]);

else

$cart[$isbn] = $$isbn;

}

$items = calculate_items($cart);

}

conta quantos itens hesistem no carrinho

function calculate_items($cart)

 {

 $items = 0;

 if(is_array($cart)){

 

 foreach($cart as $isbn => $qty)

 {

 $items += $qty;

 }

 }

 

 return $items;

 }

mostra o carrinho

function display_cart($cart, $change = true, $images = 1)

{

global $items;

global $total_price;

?>

<table border = 0 width = 100% cellspacing = 0>

<form action ='carrinho.php' method='post'>

<tr>

<th colspan = <?=(1+$images)?> bgcolor='#cccccc'>Item</th>

<th bgcolor='#cccccc'>Preco</th><th bgcolor='#cccccc'>Quant</th>

<th bgcolor='#cccccc'>Total</th></tr>

<?

foreach ($cart as $isbn => $qty)

{

?>

<tr>

<?

if($images ==true)

{

?>

<td align = left>

<?

if (file_exists("images/$isbn.jpg"))

{

$size = GetImageSize("images/".$isbn.".jpg");

if($size[0]>0 && $size[1]>0)

{

?>

<img src='images/<?=$isbn?>.jpg' border=0 width= "<?=$size[0]/3?>" height="<?=$size[1]/3?>" >

<?

}

}

else

?>

 

</td>

<?

}

?>

<td align = left>

<a href = 'show_book.php?isbn=<?=$isbn?>'><?=$book["title"]?></a> de <?=$book["author"]?>

</td><td align = center>$ <?=number_format($book["price"], 2)?>

</td>

<td align = center>

<?

if ($change == true)

{

?>

<input type = text name='<?=$isbn?>' value ='<?=$qty?>' size=3>

<?

}

else

{

print $qty;

}

?>

</td>

<td align = center>

R$ <?=number_format($book["price"]*$qty,2)?>

</td></tr>

<?

}

?>

<tr>

<th colspan = <?=(2+$images)?> bgcolor='#cccccc'> </td>

<th align = center bgcolor='#cccccc'>

<?=$items?>

</th>

<th align = center bgcolor='#cccccc'>

$ <?=number_format($total_price, 2)?>

</th>

</tr>

<?

if($change == true)

{

?>

<tr>

<td colspan = <?=(2+$images)?> </td>

<td align = center>

<input type = hidden name = save value = true> <input type ='submit' alt = 'Save Changes'>

</td>

<td> </td>

</tr>

<?

}

?>

</form>

</table>

<?

}

exibir o carriho se ele tiver algum item

if($cart && @array_count_values($cart)):

display_cart($cart);

se nao avise que o carrinho esta vazio

else:

{

?>

Seu carrinho esta vazio!!!

<hr size="1">

<? }

endif

?>

[/tr]

para testar o script execute-o :

http://localhost/carrinho.php?new=1

http://localhost/carrinho.php?new=2

http://localhost/carrinho.php?new=3

valew