QDialog with Maximize and Minimize Button

Window output from QDialog dont have Maximize and Minimize button at left top window form. We can add Maximize and Minimize at QDialog with code :

int main(int argc, char *argv[])
{
  QApplication a(argc, argv);
  Dialog w;
  w.setWindowFlags(Qt::Window); // add this.
  w.show();
 
  return a.exec();
}

Source : http://www.qtcentre.org/threads/17593-QDialog-with-Close-Maximize-and-Context-Help-Buttons