run time failure of Code2 (shown in the message)

[swoo]

Code 1 and Code 2 shown below both compile fine.

Code 1 runs fine.  But Code 2 fails during run time.  

Error message :  Access violation reading location 0x00000008.

They are identical code as far as I can tell.  What is the difference?

//--------CODE 1--------------------------------------------

#include "Simple_window.h"

#include "Graph.h"

int main() {

Simple_window win(Point(10,10), 600, 500, "Canvas");  

Axis xa(Axis::x, Point(50, 300), 400, 5, "test");

win.attach(xa);

win.show();

Fl::run();

return 0;

}

//---------CODE 2--------------------------------------------

#include "Window.h"

#include "Graph.h"

int main() {

Graph_lib::Window win(Point(10,10), 600, 500, "Canvas");  

Graph_lib::Axis xa(Graph_lib::Axis::x, Point(50, 300), 400, 5, "test");

win.attach(xa);

win.show();

Fl::run();

return 0;

}

//-----------------------------------------------------------------------------