title: PHP: Class vs Instance variables
body: <p>I know there is a difference in class variables and instance variables in programming languages like Java and C#, so I was wondering if PHP is the same.</p>
  
  <p>So I know class variables is shared among all the instances of that class whereas instance variables is only relevant to that specific instance of that class.</p>
  
  <p>For example:</p>
  
  <pre><code>class db {
    private $host;   &lt;--
    private $user;   &lt;-- These will be treated as instance variables
    private $pass;   &lt;-- as they are set by the class constructor
    private $dbname; &lt;--
  
    private $connected = false; &lt;-- Will this be treated as a class 
                                    variable? Shared among all the 
                                    instance of the db class?
  
    public function __construct($host, $user, $pass, $dbname) {
      $this-&gt;host = $host;
      $this-&gt;user = $user;
      $this-&gt;pass = $pass;
      $this-&gt;dbname = $dbname;
    }
  
    public function checkConn() {
      // some code here to change the value of $this-&gt;connected
    }
  </code></pre>