Qt - příklad
// hello.h

#include <qwidget.h>
#include <qpushbutton.h>
#include <qlayout.h>
#include <qapplication.h>

class Hello: public QWidget { 
  Q_OBJECT 
public: 
  Hello(); 
private: 
  QPushButton *button1; 
private slots: 
  void callback1(); 
}; 
// hello.cpp

#include "hello.h"

Hello::Hello(): QWidget( 0, 0 ) {
  button1 = new QPushButton("button1", this );
  connect(button1, SIGNAL(clicked()),
          this, SLOT(callback1()) );
  QVBoxLayout *main = new QVBoxLayout(this);
  main->addWidget(button1); main->setMargin(5);
}

void Hello::callback1() {
  button1->setText("clicked");
}

int main( int argc, char **argv ) { 
  QApplication a( argc, argv ); 
  Hello t;
  a.setMainWidget(&t);
  t.show(); 
  return a.exec();
}