#include <QApplication>
#include <QMainWindow>
#include <QDialog>
#include <QVBoxLayout>
#include <QPushButton>
#include <QMessageBox>
#include <QLabel>

int main( int argc, char* argv[] )
{
    QApplication app(argc, argv);

    // dialog with button opening a popup
    QMainWindow mainFrame;

    QWidget centralWidget( &mainFrame );
    centralWidget.setLayout( new QVBoxLayout() );
    QPushButton* QDialog_button = new QPushButton( "Show QDialog popup", &centralWidget );
    QPushButton* QMessageBox_button = new QPushButton( "Show QMessageBox popup", &centralWidget );
    centralWidget.layout()->addWidget( QDialog_button );
    centralWidget.layout()->addWidget( QMessageBox_button );
    mainFrame.setCentralWidget( &centralWidget );

    // QDialog-based popup
    QDialog popup( &mainFrame );
    popup.setLayout( new QVBoxLayout() );
    popup.layout()->addWidget( new QLabel( "Hello World using QDialog!", &popup ) );

    // QMessageBox-based popup
    QMessageBox message( &mainFrame );
    message.setText( "Hello World using QMessageBox!" );

    QObject::connect( QDialog_button, SIGNAL(clicked()), &popup, SLOT(exec()) );
    QObject::connect( QMessageBox_button, SIGNAL(clicked()), &message, SLOT(exec()) );

    mainFrame.show();

    return app.exec();
}