#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);

    QObject::connect(spinBox, SIGNAL(valueChanged(int)),
                     slider, SLOT(setValue(int)));
    QObject::connect(slider, SIGNAL(valueChanged(int)),
                     spinBox, SLOT(setValue(int)));
     /*如果放在connect()上面，slider窗口部件在0的位置，不是35的位置*/
    spinBox->setValue(35);     

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

    window->setLayout(layout);    
    window->show();

    return app.exec();
}