How to Include Files in PHP

 To include a file in PHP, you can use the include or require statement. These statements are used to include a file into a PHP script.

Here is an example of how to use the include statement:

<?php include 'filename.php'; ?>

The include statement will include the specified file and execute its code. If the file cannot be found, a warning will be issued, but the script will continue to execute.

Here is an example of how to use the require statement:

<?php require 'filename.php'; ?>

The require statement is similar to the include statement, but it will produce a fatal error if the file cannot be found, causing the script to stop execution.

You can also use the include_once and require_once statements, which will include the file only if it has not already been included. This can be useful if you are including the same file multiple times and you want to avoid redefining functions or variables.

<?php include_once 'filename.php'; ?>
<?php require_once 'filename.php'; ?>

It is important to note that the file being included must be a valid PHP file, with a .php extension. The file can contain any PHP code, including functions, classes, variables, and HTML.

You can use the include or require statements to include common functions or header and footer files in your PHP scripts. This can help to keep your code organized and make it easier to maintain.