include & require — PHP Technical Interview Questions & Answers

include & require

include & require

  • include 'header.php'; pastes that file here. If the file is missing, include warns and continues. require stops the page (fatal). require_once / include_once skip if already loaded — use for config.
  • Good for header/footer. Modern apps also use Composer autoload for classes.
  • Trap: include vs require on a missing config file — require is safer. Trap: path wrong relative to the current working directory.

Technical Interview Tip: require_once 'config.php'; include 'header.php';

Code Examples for include & require

include & require — working example

<?php
namespace App\\Util;

function add(int $a, int $b): int {
  return $a + $b;
}

echo \App\\Util\\add(2, 3);

include & require — namespaces organize code; require/include pull in files.

How to Explain include & require to an Interviewer

include vs require?

include warns require fatal if missing