#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();

}