variables that change session variables

[sentinel]

Hi, I'm currently writing a mulit-page form app that uses a session to
retain data from each form element in order for the user to jump
between pages, then the final data is passed to a calculation script.

However, I've noticed that if I assign a session variable to another
variable, which then performs a mathematical calculation, the session
variable changes.

i.e. $_SESSION["inflation"] = 4;
$temp_inf = $_SESSION["inflation"];
if ($_SESSION["inflation"] =="RPI") {
$inflation = $rpi;}
else {$inflation = ($temp_inf/100.0);}
now it equals = 0.04

How can I take a value from a session and perform operations on it
without altering the original session value.
Rgds
Neil.

[Per Gustafsson]

sentinel wrote:

However, I've noticed that if I assign a session variable to another
variable, which then performs a mathematical calculation, the session
variable changes.

i.e. $_SESSION["inflation"] = 4;
$temp_inf = $_SESSION["inflation"];
if ($_SESSION["inflation"] =="RPI") {
$inflation = $rpi;}
else {$inflation = ($temp_inf/100.0);}
now it equals = 0.04

How can I take a value from a session and perform operations on it
without altering the original session value.

This happends because you have the register_globals directive turned on
and thus, $_SESSION['inflation'] and $inflation contain the same value
and if you manipulate one the other changes as well.

There's two solutions to your problem, either change your naming (i.e.
switch from $_SESSION['inflation'] to $_SESSION['foo'] or from
$inflation to $bar) or turn register_globals off.
Per Gustafsson

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