/******************************************************************** Qt tutorial 8******************************************************************/#include <qapplication.h>#include <qpushbutton.h>#include <qlcdnumber.h>#include <qfont.h>#include <qlayout.h>#include "lcdrange.h"#include "cannon.h"class MyWidget: public QWidget{public:    MyWidget( QWidget *parent=0, const char *name=0 );};MyWidget::MyWidget( QWidget *parent, const char *name )        : QWidget( parent, name ){    QPushButton *quit = new QPushButton( "Quit", this, "quit" );    quit->setFont( QFont( "Times", 18, QFont::Bold ) );    connect( quit, SIGNAL(clicked()), qApp, SLOT(quit()) );    LCDRange *angle = new LCDRange( this, "angle" );    angle->setRange( 5, 70 );    CannonField *cannonField 	= new CannonField( this, "cannonField" );    connect( angle, SIGNAL(valueChanged(int)),	     cannonField, SLOT(setAngle(int)) );    connect( cannonField, SIGNAL(angleChanged(int)),	     angle, SLOT(setValue(int)) );    QGridLayout *grid = new QGridLayout( this, 2, 2, 10 );    //2x2, 10 pixel border    grid->addWidget( quit, 0, 0 );    grid->addWidget( angle, 1, 0, Qt::AlignTop );    grid->addWidget( cannonField, 1, 1 );    grid->setColStretch( 1, 10 );    angle->setValue( 60 );    angle->setFocus();}int main( int argc, char **argv ){    QApplication a( argc, argv );    MyWidget w;    w.setGeometry( 60, 60, 500, 325 );    a.setMainWidget( &w );    w.show();    return a.exec();}