[...]
#include <X11/Xlib.h>  
#include <X11/Intrinsic.h>  
#include <X11/extensions/XTest.h>  
#include <unistd.h>  

//the below function from "http://bharathi.posterous.com/x11-fake-key-event-generation-using-xtest-ext"

static void sendKBEvent (Display * display, KeySym keysym, KeySym modsym)
{
  KeyCode keycode = 0, modcode = 0;
  
  keycode = XKeysymToKeycode (display, keysym);
  
  if (keycode == 0) return;

  XTestGrabControl (display, True);

  /* Generate modkey press */
  if (modsym != 0)
  {
     modcode = XKeysymToKeycode(display, modsym);
     XTestFakeKeyEvent (display, modcode, True, 0);
  }

  /* Generate regular key press and release */
  XTestFakeKeyEvent (display, keycode, True, 0);
  XTestFakeKeyEvent (display, keycode, False, 0);

  /* Generate modkey release */
  if (modsym != 0)
    XTestFakeKeyEvent (display, modcode, False, 0);

  XSync (display, False);
  XTestGrabControl (display, False);
}


int main(int argc, char** argv)
{
   [...]
   vector<string> kbdEventsVect;

   ConfigFile configFile;
    
   kbdEventsVect = configFile.parseFile("file.txt");
   
   /*kbdEventsVect[] contains XK_Up, XK_Down, XK_Escape, XK_Right*/

   [...]
   sendKBEvent(display, kbdEventsVect[0], 0);
  [...]
 }

error: cannot convert ‘std::basic_string<char,   std::char_traits<char>, std::allocator<char> >' to   ‘KeySym' for argument ‘2' to ‘void sendKBEvent(Display*, KeySym,   KeySym)'

   sendKBEvent(display, XK_F11, 0);

sendKBEvent(display, kbdEventsVect[0], 0);