#include <QApplication>
#include <QWidget>
#include <QVBoxLayout>

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

// It doesn't work:
    QVBoxLayout layout;
    QWidget widget;
    widget.setLayout(&layout);    
    widget.show();

// It works:
//    QWidget widget;
//    QVBoxLayout layout;
//    widget.setLayout(&layout);    
//    widget.show();

// It works:
//    QWidget *widget = new QWidget;
//    QVBoxLayout *layout = new QVBoxLayout;
//    widget->setLayout(layout);    
//    widget->show();

// It works:
//    QVBoxLayout *layout = new QVBoxLayout;
//    QWidget *widget = new QWidget;
//    widget->setLayout(layout);    
//    widget->show();

    return app.exec();
}