Includes

require a file

require loads another PHP file. Failure is a fatal error.

<?php
// header.php
echo "<header>Free Computer Courses</header>\n";

// page.php
require __DIR__ . "/header.php";
echo "<main>Lesson</main>\n";

include vs require

include warns on failure; require stops. Use _once variants to avoid double loading.

require_once __DIR__ . "/helpers.php";

Use __DIR__

Build paths from the current file so includes work regardless of the working directory.

Include habits

• Keep shared layout pieces in separate files
• Do not include remote URLs
• Return values from included files only when intentional
• Composer autoloading later replaces many manual includes