Initializing variables

Anon

Forgive my ignorance, but I'm about as new as you can get to PHP. I do have some programming experience (AS,JS) and in these languages this would work, but apparently not in php. I got this code from the book PHP for flash:

<?
$count++;
print $count;
?>

When I test this I get:

Warning: Undefined variable: count in c:\program files\apache group\apache\htdocs\count.php on line 2

And then the value of $count underneith.

Why does it give me this error message yet then print the correct value?

Thanks.

Anon

first you could define count as count='0' and go from there...

Anon

Just one of the more paranoid warnings.

It's because you never gave $count a value before you incremented it. In a sense, this means that $count could be anything - usually 0, but it could possibly be something else depending on how the script was called and PHP configuration.

So the warning goes in there as a safety catch - a reminder that $count's value can't really be trusted.

Besides, you could have meant $cont, but misspelled it.

The warning can be turned off, either in php.ini or in the script with the error_reporting() function.

Anon

Thanks grumbler. So I guess it's a good idea to declare variables before you use them for anything?

Anon

The only time it could hurt is if you have register_globals turned on and using them to store the results of form variables from a previous page, so that the value from a form field like

gets referred to as $username in the script processing it.

But you shouldn't be doing that, anyway. You should be using the various $ or $HTTP_VARS arrays instead.