#include <QApplication>
#include <QFont>
#include <QLCDNumber>
#include <QPushButton>
#include <QSlider>
#include <QVBoxLayout>
#include <QWidget>

class Proxy : public QObject
{
	Q_OBJECT
	private:
		int val;
	public:
		Proxy()
		{
			val=0;
		}
		void changeValue (int na)
		{
			if (na != val)
			{
				val=na;
				emit valueChange(val);
			}
		}
	public slots:
		void newValue (int nep)
		{
			if (val!=10*nep)
			{
				val=10*nep;
				emit valueChange (val);
			}
		}
	signals:
		void valueChange (int newVal);
};

class MyWidget : public QWidget
{
	public:
		MyWidget (QWidget* parent=0);
};

MyWidget::MyWidget (QWidget *parent)
	: QWidget (parent)
{
	QPushButton *quit = new QPushButton(tr("Quit"));
	quit->setFont(QFont("Times", 18, QFont::Bold));
	QLCDNumber *lcd = new QLCDNumber(3);
	lcd->setSegmentStyle(QLCDNumber::Filled);
	QSlider *slider = new QSlider (Qt::Horizontal);
	slider->setRange(0,99);
	slider->setValue(0);

	Proxy *pro = new Proxy();

	connect(quit, SIGNAL(clicked()), qApp, SLOT(quit()));
	connect(slider, SIGNAL(valueChanged(int)), pro, SLOT(newValue(int)));
	connect(pro, SIGNAL(valueChange(int)), lcd, SLOT(display(int)));
	QVBoxLayout *layout = new QVBoxLayout;
	layout->addWidget(quit);
	layout->addWidget(lcd);
	layout->addWidget(slider);
	setLayout(layout);
}

int main(int argc, char **argv)
{
	QApplication app(argc, argv);
	MyWidget widget;
	widget.show();
	return app.exec();
}