PHP Prints unexpected number

Question

im still trying to fix my site, to display content according to the parameters in the URL, I have managed to change links and other parameters, but when it comes to choosing a correct header im lost.

This was the original code

<?php
/*
Template Name Posts: Post Template
*/

include (TEMPLATEPATH . '/header3.php'); ?>

And this worked well, now I tried to change header regarding the url parameter with such code

<?php
if (isset($_GET['ad']) && $_GET['ad'] == 1)
{
echo include (TEMPLATEPATH . '/header3.php');
}
else {
echo include (TEMPLATEPATH . '/header4.php');
}
?>

All works fine and the other header does show when parameter is present in URL, but problem is that it now prints

"1"

onto the page when I load it. I can see the modified header, but as soon as the header ends, it shows number one in main div, although there isnt such number in code. When I reverted back to the original code, then the problem was gone. Also this problem does not exist when I use modified header, with original code.

Problem is somehow connected with the parameter and then loading the correct header. Im using wordpress and need to get a special header when URL has a specific code in it.

Answer 1

change:

 echo include (TEMPLATEPATH . '/header3.php');

to:

include (TEMPLATEPATH . '/header3.php');

you need not to echong include. remove all echos then it should not be echoing 1.
see basic include doc

Answer 2

since you've echo include(), so this will display the response, which in your case is 1 for true, as your file is included...Simply remove the echo and include as :

 include(TEMPLATEPATH . '/header3.php')