FLTK - Simple Dropdown menu in C++

#include <FL/Fl.H>
#include <FL/Fl_Box.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Menu_Bar.H>

void quit_cb(Fl_Widget*, void*) { /*exit(0); */}

Fl_Menu_Item menutable[] = {
  {"&File",0,0,0,FL_SUBMENU},
    {"&Open",   FL_ALT+'o', 0, 0, FL_MENU_INACTIVE},
    {"&Close",  0, 0},
    {"&Quit",   FL_ALT+'q', quit_cb, 0, FL_MENU_DIVIDER},
    {0},
  {"&Edit",FL_F+2,0,0,FL_SUBMENU},
    {"Undo",    FL_ALT+'z',     0},
    {"Redo",    FL_ALT+'r',     0, 0, FL_MENU_DIVIDER},
    {"Cut",     FL_ALT+'x',     0},
    {"Copy",    FL_ALT+'c',     0},
    {"Paste",   FL_ALT+'v',     0},
    {"Inactive",FL_ALT+'d',     0, 0, FL_MENU_INACTIVE},
    {"Clear",   0,      0, 0, FL_MENU_DIVIDER},
    {"Invisible",FL_ALT+'e',    0, 0, FL_MENU_INVISIBLE},
    {"Preferences",0,   0},
    {"Size",    0,      0},
    {0},
  {0}
};


int main(int argc, char **argv) {
  Fl_Window window(600,400);
  Fl_Menu_Bar menubar(0,0,600,30);
  menubar.menu(menutable);

  window.size_range(300,400,0,400);
  window.end();
  window.show(argc, argv);
  return Fl::run();
}