title: Why declare class' properties when constructor initialize this properties
body: <p>Write what is best and why?</p>
  
  <pre><code>class Chat
  {
      private $_couleur;
      private $_race;
  
      function __construct($couleur, $race)
      {
          $this-&gt;_couleur = $couleur;
          $this-&gt;_race = "$race";
      }
  
      public function getCouleur() {
          return $this-&gt;_couleur;
      }
  }
  </code></pre>
  
  <p>Or</p>
  
  <pre><code>class Chat
  {
      function __construct($couleur, $race)
      {
          $this-&gt;_couleur = $couleur;
          $this-&gt;_race = "$race";
      }
  
      public function getCouleur() {
          return $this-&gt;_couleur;
      }
  }
  </code></pre>
  
  <p>Because <code>$this-&gt;_couleur</code> is initialized when the class is instancied, so declare the property directly in the class is useless, isn't ?</p>