title: Use of colon after class name in c++
body: <p>This is a header file extracted from a blackberry 10 helloworld program. </p>
  
  <pre><code>#ifndef ApplicationUI_HPP_
  #define ApplicationUI_HPP_
  
  #include &lt;QObject&gt;
  
  namespace bb
  {
      namespace cascades
      {
          class Application;
          class LocaleHandler;
      }
  }
  
  class QTranslator;
  
  /*!
   * @brief Application object
   *
   *
   */
  
  class ApplicationUI : public QObject
  {
      Q_OBJECT
  public:
      ApplicationUI(bb::cascades::Application *app);
      virtual ~ApplicationUI() { }
  private slots:
      void onSystemLanguageChanged();
  private:
      QTranslator* m_pTranslator;
      bb::cascades::LocaleHandler* m_pLocaleHandler;
  };
  
  #endif /* ApplicationUI_HPP_ */
  </code></pre>
  
  <p>I am confused about the colon operator right after the class name declaration.</p>
  
  <pre><code>class ApplicationUI : public QObject
  </code></pre>
  
  <p>What does this mean?</p>