C ++ exercises (2)

1,
# Include <qapplication>
# Include <qlabel>

Int main (INT argc, char * argv [])
{
Qapplication app (argc, argv );
// Qlabel lbinfo ("Hello, world", 0 );
Qlabel * lbinfo = new qlabel ("Hello, world", 0 );
// Lbinfo. Show ();
Lbinfo-> show ();
Return app.exe C ();
}
2,
# Include <qapplication>
# Include <qpushbutton>

Int main (INT argc, char * argv [])
{
Qapplication app (argc, argv );

// Qpushbutton btnok ("OK", 0 );
Qpushbutton * btnok = new qpushbutton ("OK", 0 );
Btnok-> resize (300,200 );
Qobject: connect (btnok, signal (clicked (), & App, slot (quit (); // connect the signal to the slot.
Btnok-> show ();
Return app.exe C ();
}
3,
# Include <qapplication>
# Include <qwidget>
# Include <qslider>
# Include <qspinbox. h>

Int main (INT argc, char * argv [])
{
Qapplication app (argc, argv );

Qwidget * centralwidget = new qwidget (0 );

Qspinbox * spbox = new qspinbox (centralwidget );
Qslider * slider = new qslider (QT: horizontal, centralwidget );
Spbox-> setgeometry (qrect (20, 20, 44, 22 ));
Slider-> setgeometry (qrect (90, 20,160, 21 ));
Spbox-& gt; setrange (0,140 );
Slider-> setrange (0,140 );

Qobject: connect (spbox, signal (valuechanged (INT), Slider, slot (setvalue (INT); // connect the signal to the slot.
Qobject: connect (slider, signal (valuechanged (INT), spbox, slot (setvalue (INT); // connect the signal to the slot.

Spbox-> setvalue (32 );
Centralwidget-> show ();
Return app.exe C ();
}