Difference between declaring variables inside or outside of constructor?
<p>For example is there a difference between the two?  Is one preferred to the other?</p>

<pre><code>Class Node{    
    public $parent = null;
    public $right = null;
    public $left = null;            
    function __construct($data){
        $this-&gt;data = $data;                    
    }
}

Class Node{     
    function __construct($data){
        $this-&gt;data = $data;      
        $this-&gt;parent = null;       
        $this-&gt;left = null;       
        $this-&gt;right = null;               
    }
}
</code></pre>
