Basic animation doesn't fire - c++

Question

I'm trying to follow this example to create an animation:
http://seriss.com/people/erco/fltk/#Animate
Except for the fact that instead of changing the image I'm moving it. There's a car image that should move in a down-right direction every half second, for 10 times:
void func(void* data)
{
static int counter=0;
counter++;
Fl_PNG_Image* image= static_cast<Fl_PNG_Image*>(data);
Fl_Box* box= new Fl_Box(counter*10, counter*10,100,100);
box->image(image);
//delete box;
window->redraw();
if(counter==10)
{
Fl::remove_timeout(func,data);
}
else
{
Fl::repeat_timeout(.5,func,data);
}
}
int main(int argc, char **argv)
{
window = new Fl_Double_Window(width, height);
Fl_PNG_Image* image= new Fl_PNG_Image("car-down.png");
Fl_Box* box= new Fl_Box(0,0,100,100);
box->image(image);
Fl::add_timeout(.5, func, image);
//delete box;
window->end();
window->show(argc, argv);
return Fl::run();
}
I have two problems:
I can't understand when I should delete the box. I'm using it to draw the image, and if I delete it immediately after having drawn the image, the image disappears.
The image doesn't move, and it always stays on the initial position.

Answer 1

Instead of creating new boxes and images, move the box. The box will be deleted when the window is closed
void func(void* data)
{
static int counter=0;
counter++;
//Fl_PNG_Image* image= static_cast<Fl_PNG_Image*>(data);
Fl_Box* box= static_cast<Fl_Box*) data;
box->position(counter*10, counter*10);
window->redraw();
...
}
int main(int argc, char **argv)
{
...
Fl::add_timeout(.5, func, box);
window->end();
window->show(argc, argv);
return Fl::run();
}