void CraytDlg::OnBnClickedOk() { CDC *pDC = GetDC(); LARGE_INTEGER F,T0,T1; // address of current frequency QueryPerformanceFrequency(&F); QueryPerformanceCounter(&T0); motor.render(pDC); QueryPerformanceCounter(&T1); float elapsed_time = (float)(T1.QuadPart - T0.QuadPart) / (float)F.QuadPart; char buffer[255]; sprintf(buffer,"%g s" , elapsed_time); AfxMessageBox(buffer); ReleaseDC(pDC); }