#include <QtGui>

class MyWidget : public QWidget
{
    Q_OBJECT
public:
    MyWidget(QWidget *parent = 0) : QWidget(parent)
    {
        QPushButton* closebutton = new QPushButton("Close");
        closebutton->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
        QVBoxLayout* layout = new QVBoxLayout(this);
        layout->addWidget(closebutton);

        connect(closebutton, SIGNAL(clicked()),this, SLOT(close()));
    }
};

#include "main.moc"

int main(int argc, char **argv)
{
    QApplication a(argc, argv);
    MyWidget w;
    w.showMaximized();
    return a.exec();
}