MyWebView::createWebView()
{
   webView = new QWebView(parentWindow);
   parentWindow->setCentralWidget(webView);
}

class QTParentWindow : public QMainWindow, public MyParentWindow

QTParentWindow::QTParentWindow()
: objMyWebView(this) // passing this which is stored as parentWindow in MyWebView class
{
   objMyWebView.createWebView();
}

int main()
{
  MyParentWindow * obj = new QTParentWindow();
  obj.show();
}