Undifine variable notice help. Doesn't look to pretty on the screen

PHP
1 
$result = mysql_query("SELECT * FROM cart INNER JOIN kb ON cart.id = kb.id WHERE cart.cookieId = '" . GetCartId() . "' ORDER BY kb.name ASC");?>

<?php while($row = mysql_fetch_array($result))
{
// Increment the total cost of all items
$totalCost += ($row["qty"] * $row["price"]); line 207
?>

<b>Notice</b>: Undefined variable: totalCost in <b>C:\wamp\www\store\cart.php</b> on line <b>207</b><br />

The price is coming from kb table and qty is coming form cart. I don’t know why it is throwing this undefine variable notice. to my knowledge I think the variable is defined as it is. Please any body has any comments on why it is throwing this notice?

Thank you

2

The reason you get an undefined var notice is pretty simply because you are trying to use undefined variables
<?php
$totalCost = 0; // now it is defined you can do stuff like += with it
while($row = mysql_fetch_array($result))
{
// Increment the total cost of all items
$totalCost += ($row[“qty”] * $row[“price”]); line 207
?>

3

Thank you Hash!