[Resolved] Simple math doesn't always work

szym9341

The following brings in three variables from a form... if these variables are small numbers, all is well... if these variables are high (above 20 or so), the 'total including tax line' is extremely low... any ideas?!?!?

<?
echo "Order processed at ";
echo date("H:i, jS F");
echo " ";
echo "Your order is as follows: ";
echo $POST["tireqty"]." tires ";
echo $POST["oilqty"]." containers of oil ";
echo $POST["sparkqty"]." spark plugs ";
$totalqty = 0;
$totalamount = 0.00;
define("TIREPRICE", 100);
define("OILPRICE", 10);
define("SPARKPRICE", 4);
$totalqty = $POST["tireqty"] + $POST["oilqty"] + $POST["sparkqty"];
$totalamount = $POST["tireqty"] TIREPRICE
+ $POST["oilqty"] OILPRICE
+ $_POST["sparkqty"] SPARKPRICE;
$totalamount = number_format($totalamount, 2);
echo " \n";
echo "Items ordered: ".$totalqty." \n";
echo "Subtotal: $".$totalamount." \n";
$taxrate = 0.10; //local tax rate
$totalamount = $totalamount (1 + $taxrate);
$totalamount = number_format($totalamount,2);
echo "Total including tax: $".$totalamount." \n";
?>

szym9341

Narrowing it down a little more I find:

Everything works fine up until the subtotal reaches $1000.00

At 996.00, all is well

At 1000.00, the Total including Tax becomes incorrect yielding $1.10 or a small number like that

drew010

id just do something like this:

$taxrate = 0.10; //local tax rate
$totalamount += ($totalamount * $taxrate);

szym9341

Thank you.. I tried that but it still causes an error when the subtotal reaches $1000.00

leatherback

Hi,

Sounds like you have a problem with the number format, where a thousands seperator is used for a decimal indicator or something. Have you looked at the options for number_format()?

Try:

number_format($totalamount,2, '.', '.');

drew010

yeah i tested that out on my server and it worked fine with any value over 1000. seems you are having some other kind of problem.

szym9341

I have tried many format_number options... nothing seems to work with the subtotal reaches a value of $1000

leatherback

Could you post the output you get if you set the total amount to 1000?

szym9341

Below is a copy when all is well (Subtotal adds up to less than $1000.00)

Your order is as follows:
7 tires
10 containers of oil
25 spark plugs

Items ordered: 42
Subtotal: $900.00
Total including tax: $990.00

Below is a copy when Subtotal is over $1000.00

Your order is as follows:
9 tires
15 containers of oil
50 spark plugs

Items ordered: 74
Subtotal: $1,250.00
Total including tax: $1.10

drew010

the variable $totalamount is probably being treated as a string when its over 1000 because you have a comma in it from being number formatted above the tax part. either create separate variables that get number formatted or just output them.

example:

$totalamount = number_format($totalamount, 2);
//right there above, anything over 1000 goes from int(1000)
//to string("1,000")
...
...
...
$taxrate = 0.10; //local tax rate
$totalamount = $totalamount * (1 + $taxrate);
//the above is trying to add a string so it will just drop everything
//after the comma, to turn in into an integer
// so 1 + .10 = 1.10 as shown in your example output.

$totalamount = number_format($totalamount,2);
echo "Total including tax: $".$totalamount." \n";