3d vector rotation

void CVector3D::Rotate(double rotx, double roty, double rotz)
    {
    CVector3D result(x, y, z);

    if (rotx)
        {
                result.y += (double)(y*cos(rotx) - z*sin(rotx));
        result.z += (double)(y*sin(rotx) + z*cos(rotx));
        }
    if (roty)
        {
        result.x += (double)(x*cos(roty) + z*sin(roty));
        result.z += (double)(- x*sin(roty) + z*cos(roty));
        }
    if (rotz)
        {
        result.x += (double)(x*cos(rotz) - y*sin(rotz));
        result.y += (double)(x*sin(rotz) + y*cos(rotz));
        }

    *this = result;
    }