// Листинг 1.3. Программа эхо-печати

#include <xstring>
typedef std::basic_string<TCHAR, std::char_traits<TCHAR>,
std::allocator<TCHAR> > String;
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
   PAINTSTRUCT ps;
   HDC hdc;
   static String str;
   switch (message)
   {
   case WM_CHAR:
      str += (TCHAR)wParam;
      InvalidateRect(hWnd, NULL, TRUE);
      break;
   case WM_PAINT:
      hdc = BeginPaint(hWnd, &ps);
      TextOut(hdc, 0, 0, str.data(), str.size());
      EndPaint(hWnd, &ps);
      break;
   case WM_DESTROY : PostQuitMessage(0); break;
   default : return DefWindowProc(hWnd, message, wParam, lParam);
   }
   return 0;
}