title: What's the equivalent of virtual functions of c++ in PHP?
body: <p>Is it <code>abstract function xxx</code>?</p>
  
  <p>I just made a test which seems to indicate a private method to be virtual too?</p>
  
  <pre><code>class a {
   private function test()
   {
    echo 1;
   }
  }
  
  class b extends a {
   private function test()
   {
    echo 2;
   }
   public function call()
   {
    $this-&gt;test();
   }
  }
  
  $instance = new b;
  $instance-&gt;call();
  </code></pre>
  
  <p>The output is <code>2</code></p>