public Point3D(Point3D other)
: base((Point2D)other)
{
this.z = other.z;
}
public Point3D Add(Point3D p2)
{
return new Point3D(x + p2.x, y + p2.y, z + p2.z);
}
public Point3D Subtract(Point3D p2)
{
return new Point3D(x - p2.x, y - p2.y, z - p2.z);
}