Undefined Index!!!???

[Savaal]

Ok, I am about to pull all of my hair out on this one...

I have a form that passes 50 or so vars through post, which works fine. It passes them to a parse script, which I use to turn my post vars to session vars. They then go to a mathematics script that does simple math on the session variables, such as this...

$SESSION['sum'] = ($SESSION['digita']+$_SESSION['digitb']);

and some simple if statements to set the var to 0 if it is null.

The problem is that I worked for two hours to make the script work, due to getting Undefined Index errors. I found that it had to do with my quotes... For example...

If I did it like this

$_SESSION['sum']

I would get an Undefined index error, but if I did it like this...

$SESSION[sum] or '$SESSION[sum]', it would work, but only if it were in perenthesis, if you can believe it... If it weren't in perenthesis, I would get a Use of undefined constant notice.

So after changing my quotes for two hours, it worked... Until I closed my browser. Now it does the same thing... But with a twist... Keep in mind that nothing has changed since it worked. Here goes...

I get 100 or so Undefined Index errors, but if I hit refresh, about half of them go away...

???????????

Help Please!!!!

[Weedpacket]

Session variables - like other variables - are undefined until you put something in them. If you never put anything in $SESSION['digita'] before running the script, then $SESSION['digita'] will be undefined. The array is there, because you call session_start(), but the index 'digita' wasn't. You should check using isset() to make sure that they have values before trying to use those values.

They work after the refresh because they would have had values by then (after the script ran the first time and threw all those notices).

PS: you should be using the quotes - $_SESSION[sum] is bad (unless inside a string).