PHP Comments and File Inclusion Day 4

PHP Comments and File Inclusion Day 4

1. PHP Comments

Comments are essential for making code understandable for future developers or even yourself when revisiting old projects. They don't affect execution but provide clarity about the code's purpose.

Types of Comments

1. Single-line comments:

   php
   // This is a single-line comment
   

2. Multi-line comments:

   php
   /* 
      This is a multi-line comment.
      Useful for documenting longer notes. 
   */
   

Importance of Comments

• Collaboration: Helps team members understand the code.
• Code Reusability: Assists when reusing or modifying old projects.
• Professional Standards: Enhances code quality and marketability.

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2. File Inclusion in PHP

File inclusion allows you to reuse code, making development efficient and consistent.

2.1 include and include_once

• include: Adds a file. If the file is missing, a warning is issued, but the script continues.

  php
  include 'header.php';
  

• include_once: Ensures the file is included only once, avoiding duplication.

  php
  include_once 'header.php';
  

2.2 require and require_once

• require: Adds a file. If the file is missing, it raises a fatal error and stops the script.

  php
  require 'config.php';
  

• require_once: Ensures the file is added only once.

  php
  require_once 'config.php';
  

Example: Shared Header

• File: header.php

  html
  <a href="/index.php">Homea>
  <a href="/aboutus.php">About Usa>
  <a href="/services.php">Servicesa>
  <a href="/contactus.php">Contact Usa>
  

• File: index.php

  php
  include 'header.php';
  

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3. include vs. require

Aspect	include	require
Error Handling	Issues a warning.	Raises a fatal error.
Script Execution	Continues after a warning.	Stops if the file is missing.

Best Practices

• Use include for non-critical files like headers or footers.
• Use require for essential files like database configurations.

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4. Summary

• Comments enhance code readability and collaboration.
• File Inclusion simplifies reusing code like headers, footers, and configurations.
• Use include for optional files and require for mandatory ones.

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