这种类定义格式是什么意思 class QwtPlotCurve::PrivateData

[cPlusPlus小学生]

class QwtPlotCurve::PrivateData
{
public:
PrivateData():
style( QwtPlotCurve::Lines ),
baseline( 0.0 ),
symbol( NULL ),
attributes( 0 ),
paintAttributes(
QwtPlotCurve::ClipPolygons | QwtPlotCurve::FilterPoints ),
legendAttributes( 0 )
{
pen = QPen( Qt::black );
curveFitter = new QwtSplineCurveFitter;
}

~PrivateData()
{
delete symbol;
delete curveFitter;
}

..............
};

[ouyh12345]

QwtPlotCurve应该是某个命名空间或类

[buyong]

类中的类？

[Saleayas]

class C
{
	class CC;
	int a;
};

class C::CC
{
	int a;
};