Understanding directory linkage in php
<p>I need some help in understanding how directory paths and file linking works. I am testing this on a local server.</p>

<p>If I have the following files in the <strong>ROOT Directory</strong>:<br />
- <strong>includes [folder]</strong><br />
-- <strong>index.php [php file inside includes folder]</strong><br />
- <strong>adm [folder]</strong><br />
  -- <strong>constant.php [php file inside adm folder]</strong> </p>

<p>I want to require "constant.php" inside the "index.php", how can I do that?</p>

<p><em>Another confusion is that what is the difference between real path and relative path in PHP?</em></p>
