Digital Compass difficulty

Hi, can someone see whats wrong with this formula/code? the compas works perfectly for North, south, east, west, but not the values inbetween. its very inaccurate in between.

Code:

float Instrument::bearing(QPointF *src, QPointF *dest) {
 
    float dLon = dest->y() - src->y();
 
    float y = sin(dLon) * cos(dest->x());
    float x = cos(src->x()) * sin(dest->x()) - sin(src->x()) * cos(dest->x()) * cos(dLon);
    float brng = atan2(x, y); 
 
 
    qDebug() << brng << "BRNG !!!!!!!!!!!!!!!!!!!";
    brng *= 180/(4.0*atan(1.0));                            // 180/pi
    int deg = (((int)brng + 360) % 360);
 
    return deg;

Please help =)

thanks,
Badeand

Added after 49 minutes:

Sorry guys I fixed it =)

This did the trick:

Code:

float Instrument::bearing(QPointF *src, QPointF *dest) {
 
 
    qreal y = dest->y() - src->y();
    qreal x = (dest->x() - src->x());
    qreal brng = atan2(x, y);
 
 
    qDebug() << brng << "BRNG !!!!!!!!!!!!!!!!!!!";
    brng *= 180/(4.0*atan(1.0));                            // 180/pi
    int deg = (((int)brng + 360) % 360);
 
    return deg;
}

love,
Badeand