QStackedWidget Problem

Dear Friends

Code:

class COptWidget : public QWiget
{
	Q_OBJECT
public:
	COptWidget(SomeOtherClass *parent=0);
	~COptWidget();
};
 
COptWidget *plotopt = new COptWidget(pointerToSomeOtherClass);
QStackedWidget  *curPlot =  new QStackedWidget;
curPlot->addWidget(plotopt);
curPlot->setCurrentWidget(plotopt);

But with this I am not able to see the plot what am I missing here. Application crashed at curPlot->addWidget(plotopt);