text: // Chapter 21, exercise 11: provide a GUI interface for entering Orders into
  // files
  
  #include "chapter21_ex11_Simple_window.h"
  
  using namespace Graph_lib;
  
  int main()
  try {
      Order_enter_window oewin;
      return gui_main();
  }
  catch (exception& e) {
      cerr << "exception: " << e.what() << '\n';
      keep_window_open();
  }
  catch (...) {
      cerr << "exception\n";
      keep_window_open();
  }