获取windows系统版本

 OSVERSIONINFOEX osVersionInfo;
 ZeroMemory(&osVersionInfo, sizeof(OSVERSIONINFOEX));
 osVersionInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
 if (!GetVersionEx((LPOSVERSIONINFO) &osVersionInfo))
 {
  _tprintf(_T("GetVersionEx failed w/err 0x%08lx\n"), GetLastError());
  return 1;
 }
 if(osVersionInfo.dwPlatformId == 2 && osVersionInfo.dwMajorVersion == 6 && osVersionInfo.dwMinorVersion == 1)
 {
  CRect rcClient;
  m_pMonthCal = new CMonthCalCtrl();
  m_pMonthCal->Create(WS_VISIBLE | WS_CHILD | MCS_NOTODAY ,CPoint(107,165),this,0x5000);
  m_pMonthCal->GetClientRect(rcClient);
  m_pMonthCal->MoveWindow(107,165,rcClient.Width(),rcClient.Height());
 }
 else
 {
  m_monthcalctrl_choose.ShowWindow(SW_SHOW);
 }