HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);
hr = CoCreateInstance(CLSID_CUIAutomation8, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pUIAutomation));
if (SUCCEEDED(hr))
{
    // Test with french or english calc
    HWND hWndDest = FindWindow(L"ApplicationFrameWindow", L"Calculatrice");
    if (!hWndDest)
        hWndDest = FindWindow(L"ApplicationFrameWindow", L"Calculator");
    if (hWndDest)
    {
        if (IsIconic(hWndDest))
        {
            ShowWindow(hWndDest, SW_RESTORE);
            Sleep(200);
        }
        IUIAutomationElement* pRoot = NULL;
        hr = pUIAutomation->ElementFromHandle(hWndDest, &pRoot);
        if (SUCCEEDED(hr))
        {
            IUIAutomationCondition* pTrueCondition = NULL;
            hr = pUIAutomation->CreateTrueCondition(&pTrueCondition);
            IUIAutomationElementArray* pElementArray = NULL;
            hr = pRoot->FindAll(TreeScope_Descendants, pTrueCondition, &pElementArray);
            if (SUCCEEDED(hr))
            {
                int nCount;
                hr = pElementArray->get_Length(&nCount);
                for (int i = 0; i < nCount; i++)
                {
                    {
                        IUIAutomationElement* pElement = NULL;
                        hr = pElementArray->GetElement(i, &pElement);
                        if (SUCCEEDED(hr))
                        {
                            BSTR bstrId;
                            pElement->get_CurrentAutomationId(&bstrId);
                            if (lstrcmp(bstrId, L"num8Button") == 0)
                            {
                                IUnknown* pUnknown = NULL;
                                IUIAutomationLegacyIAccessiblePattern* pLegacyIAccessiblePattern = NULL;
                                hr = pElement->GetCurrentPattern(UIA_LegacyIAccessiblePatternId, &pUnknown);
                                hr = pUnknown->QueryInterface(IID_PPV_ARGS(&pLegacyIAccessiblePattern));
                                if (SUCCEEDED(hr))
                                {
                                    hr = pLegacyIAccessiblePattern->DoDefaultAction();
                                    pLegacyIAccessiblePattern->Release();
                                }
                            }
                            pElement->Release();
                        }
                    }
                }
            }
            pTrueCondition->Release();
            pRoot->Release();
        }
    }
    pUIAutomation->Release();
}