Simple Math Problem

phplearner

How embarrassing...I looked at the Match functions but can't get this simple stuff to work.

$unitprice = "10.00";
$tax = "0.825";
$shipping = "5.00";

$total = $unitprice * $tax;
$total = $total + $shipping;

The actual tax is 0.825 ... I need to round up to .xx ... so, .825 would be .83 whereas .824999 would be .82 and...

...the answer &should* be: 10.00 + .83 + 5.00 = $15.83 but I get $5.285 which is, of course, wrong.

Thanks to anyone who can help...including the rounding up/down based upon the .xxY "Y" position to only 2 decimal places.

(EDIT🙂 Oh "Duh!" (on me) ... I must add the calculated $tax TO the $total. There must be some elegant way of doing all this?
This:

$total = $unitprice * (1 . $x_tax);

... gives me $15.825 but still need to get to $15.83 (or $15.82 if the tax is 0.82000 through 0.824999.

(EDIT#2):
OK...I get this to work in the HTML section:

Total Amount : <?=printf('%.2f', $total;?> <BR />

It just seems a bit 'messy' ???

programmer79

$unitprice = "10.00"; 
$tax = round(0.0825, 3);
$shipping = "5.00"; 

$total = ($unitprice * (1 + $tax)) + $shipping;

echo $total;

your tax was calculating at .825 or 82.5% rather than .0825, anyway this should do it for you.

phplearner

programmer79:

Thanks...but I can not use a 'fixed' tax amount (thus, the reason for $tax ... because the rate will vary.

Umh, I also forgot $unitprice must be multiplied by $quantity BEFORE the $tax is calculated and the $ship added.

So at the first, I'm now doing:

$total = $unitprice * $quantity;

But this isn't working. Gheeezzz...I used to be good at math.

(EDIT again🙂Umh, I solved this problem...needed to add a $_SESSION['blah'] part.

Obviously, I did NOT get enough sleep last night :mad:

programmer79

$tax = ".0825";
$unitprice = "10.00"; 
$quantity = 2;
$total = $unitprice * $quantity;

$tax = round($tax, 3);
$shipping = "5.00"; 

$total = ($total * (1 + $tax)) + $shipping;

Try that.

phplearner

Gheeezzzz...I can't believe how screwed up I am today :rolleyes:

I appreciate your help & sorry to be so discomboobulated here.

Somehow, I also overlooked the fact I need to display a Sub-Total. So the final scenario here is:

Multiply $quantity TIMES $unitprice = $subtotal
Calculate the total $tax ($subtotal TIMES $salestax) = $subtotal2
Then ADD $ship TO $subtotal2 = "Grand" $total

ARRGGGHHH!!!!

phplearner

This is bizarre...everything works on my PC but calculations don't work on the final page up on the Unix.

It is "one of those days" here :o

programmer79

What type of error are you getting on the server?

phplearner

Hello again, programmer79:

Well, I got it all working...on my PC test station, but nothing transfer from page to page in Sessions on the Unix. I've tried everything and have some other posts out but still no luck.

I changed the $variables to match several which get passed to Authorize.Net, so this is a bit "Rube Goldberg" but it works:

$subtotal = $unitprice * $quantity;
$x_tax = $subtotal * $salestax;
$subtotal2 = $subtotal + $x_tax;
$x_Amount = $subtotal2 + $x_freight;
$x_Amount = number_format( $x_Amount, 2 )

...and the HTML portion:

Description: <?=$x_Description?>  <BR />
Sub-Total: <?=number_format($subtotal,2)?> <BR />
Sales Tax: <?=number_format($x_tax,2)?> <BR />
Shipping: <?=$x_freight?> <BR />
Total Amount: <?=printf('%.2f', $x_Amount)?> <BR />

... 'hidden' stuff omitted.

Regards,

DeadlySin3

How do you have PHP configured on your home station? register_globals = On? Off?

And how about on the unix server?

It does make a difference...

if register_globals = On
on your home work station, the following code would work.

<?php
session_start();

if(session_is_registered("username")) 
{
echo "Welcome Back, $username";
// Print user specific page here
} // end IF

else {
// Print your default page here
?>

<form action="<?=$PHP_SELF?>" method="POST">
<input type="text" name="username">
<br />
<input type="submit" value="Register Your User Name">
</form>
<?php
} // end ELSE

if($username) {
session_register("username");
}
?>

If you had register_globals = Off
then it would not work. The following would though...

<?php
session_start();
if($_SESSION['username']) 
{
echo "Welcome back, {$_SESSION['username']}";
// print your user specific page here
} // end IF

else {
$self=$_SERVER['PHP_SELF'];
// Print your default page here
?>

<form action="<?=$self?>" method="POST">
<input type="text" name="username">
<br />
<input type="submit" value="Register Your User Name">
</form>
<?php
} // end ELSE

if($_POST['username']) 
{
$username=$_POST['username'];
$_SESSION['username'] = $username;
}
?>

I guess the point i'm trying to convey here is register_globals can be a pain. Best bet is to code for them to be off, then your application should work either way.

Hope this helps you out!

phplearner

Hello:

Thank you for all your input and suggestions.

Yes, Register_globals is MORE than a 'pain' ... for over a year now (since the default=OFF scenario), the majority of scripts I've downloaded to try are worthless 'cuz they require globals ON. The frustrating part is that no one seems to care about specific labeling them WILL or WILL NOT work with rg_OFF.

Unforuntatlely, my ISP did NOT compile PHP for the AIX Unix with "session.use_trans_sid" = 1 ... it is "Off", and therefore I am screwed.

I've tried adding ini_blah fixes in the scripts and even in an .htaccess file to temporarily override the settings per the PHP manual but it doesn't work.

ARRRRRRRRRRRGGGGGGGGGGHHHHHHHHHHHHH!!!