Including multiple PHP files.

Use of Including files.

• Including multiple PHP files helps Maintainability
• Huge blocks of code can be split into small useful blocks which can be included wherever necessary.
• Re-usability of code.

How To 

1. Using Require.
• Produces a fatal-error (E_COMPILE_ERROR) and stops the script if the Code fails to load the Script file.
2. Using Include. 
• Produces a warning (E_WARNING) and Resumes the script upon failure. 

Based on Requirements choose whether to use Require or Include. 
 

 Syntax :  

<?php include 'script_name.php '  ?>

<?php require 'script_name.php'  ?>

Example

---

<!-- test.php --> 

echo " Hello World <br/>" ;

echo "This Message is Displayed  by the Included file test.php <br/> " ;

---

---

<!-- Main.php -->

<?php 

    echo "This is Displayed from main.php <br/>";

    include "test.php";

?> 

---

 Output

This is Displayed from main.php
Hello World
This message is Displayed from Test.php

For more Information refer

1. http://www.w3schools.com/php/php_includes.asp
2. http://www.php.net/manual/en/function.include.php