calculating subtotal and total from basic shopping cart script

Im trying to calculate a subtotal and a total from a series of values stored in an array returned from a mysql database.

this i what i have thusfar

    while($row = mysql_fetch_array($cart)){ 
    foreach($row AS $key => $value) { $row[$key] = stripslashes($value); } 
    $id = $row['id'];
    $contents = unserialize($row['contents']);
        foreach( $contents as $key => $value){
            if($key == "price"){$subtotal = $subtotal+$value;}
            echo "$key : $value <br />";
        }
    echo "<br><br><br>";
    } 
echo "<font color=red>SubTotal $subtotal</font>";

$contents contains an array [name] => super [price] => 65.87 [quantity] => 25

So i need to multiply the price by quantity, and then take that subtotal (per ite开发者_Python百科m) and add it in total after the loop

foreach( $contents as $key => $value)
{
   if($key == "price") $total = $total+$value;

   if($key == "name")
   { 
       if(!isset($subtotal[$key])) $subtotal[$key] = 0;
       $subtotal[$key] = $subtotal[$key] + $value;
   }
}

Then you have total price in $total and for each individual item in $subtotal array

I'm not sure what you mean for total and subtotal. I assume that subtotal is the price of an item times his quantity.

For Total I assume you intend the subtotal you print in red.

Your code become:

$total=0;
while($row = mysql_fetch_array($cart)){ 
    foreach($row AS $key => $value) { $row[$key] = stripslashes($value); } 
    $id = $row['id'];
    foreach($row AS $key => $value) { $row[$key] = stripslashes($value); } 
    $id = $row['id'];
    $contents = unserialize($row['contents']);
    $contents['subtotal'] = $contents['price']*$contents['quantity'];
    foreach($contents as $key => $value){echo "$key : $value <br />"; }
    $total +=$content['subtotal'];
} 
echo "<font color=red>Total: $total</font>";

If the formatting is not mandatory I would use a slight different solution for formatting the output. (you should check the printf format string placeholder syntax)

$billLine = "%s (%0.2f x %d): %0.2f<br /><br /><br />";
$total=0;
while($row = mysql_fetch_array($cart)){ 
    foreach($row AS $key => $value) { $row[$key] = stripslashes($value); } 
    $id = $row['id'];
    foreach($row AS $key => $value) { $row[$key] = stripslashes($value); } 
    $id = $row['id'];
    $contents = unserialize($row['contents']);
    $subtotal = $contents['price']*$contents['quantity'];
    printf($billLine, $contents['name'],
                      $contents['quantity'],
                      $contents['price'],
                      $subtotal);
    $total +=$subtotal;
} 
echo "<font color=red>Total: $total</font>";