Class definition, the meaning of additional parameters

I can't remember what it means when there are objects,variables stated between a Classes name and the opening brace. An example of what I mean is shown below (taken from the Qwt code) and emboldened.

Code:

AttitudeIndicator::AttitudeIndicator(
        QWidget *parent):
    QwtDial(parent),
    d_gradient(0.0)
{
    setMode(RotateScale);
    setWrapping(true);

    setOrigin(270.0);
    setScaleOptions(ScaleTicks);
    setScale(0, 0, 30.0);
    //setRange(0.0,360.0,1.0,1.0);

    const QColor color =
#if QT_VERSION < 0x040000
        colorGroup().text();
#else
        palette().color(QPalette::Text);
#endif

    setNeedle(new AttitudeIndicatorNeedle(color));
}

Could someone tell me what it means to have the lines as shown ?

This is the initialization list, the only way to actually initialize class members / bases.

Random link to a tutorial.

Originally Posted by anon

This is the initialization list, the only way to actually initialize class members / bases.

Random link to a tutorial.

Thanks anon !