title: what is the difference between extends and normal calling?
body: <p>What is the difference between two codes?</p>
  
  <p>Extends;</p>
  
  <pre><code>&lt;?php 
  require_once 'example.class.php';
  Class First extends Example
  {}
  ?&gt;
  </code></pre>
  
  <p>Normal calling;</p>
  
  <pre><code>&lt;?php
  require_once 'example.class.php';
  Class First
  {
      public $example;
      function __construct()
      {
          $this-&gt;example = new Example();
      }
  }
  ?&gt;
  </code></pre>
  
  <p>I know some difference for example using protected pharase.
  But this is not enough in my opinion.</p>