c++ gui qt4 chap01 age

<age.cpp>

#include <QApplication>
#include <QHBoxLayout>
#include <QSlider>
#include <QSpinBox>

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

QWidget *window = new QWidget;
window->setWindowTitle("Enter Your Age");

QSpinBox *spinBox = new QSpinBox;
QSlider *slider = new QSlider(Qt::Horizontal);
spinBox->setRange(0, 130);
slider->setRange(0, 130);

QObject::connect(spinBox, SIGNAL(valueChanged(int)),
slider, SLOT(setValue(int)));
QObject::connect(slider, SIGNAL(valueChanged(int)),
spinBox, SLOT(setValue(int)));
spinBox->setValue(35);

QHBoxLayout *layout = new QHBoxLayout;
layout->addWidget(spinBox);
layout->addWidget(slider);
window->setLayout(layout);

window->show();

return app.exec();
}