#include <windows.h>

#include <shobjidl.h>

#include <atlbase.h> // Contains the declaration of CComPtr.

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow)

{

    HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED |

        COINIT_DISABLE_OLE1DDE);

    if (SUCCEEDED(hr))

    {

        CComPtr<IFileOpenDialog> pFileOpen;

        // Create the FileOpenDialog object.

        hr = pFileOpen.CoCreateInstance(__uuidof(FileOpenDialog));

        if (SUCCEEDED(hr))

        {

            // Show the Open dialog box.

            hr = pFileOpen->Show(NULL);

            // Get the file name from the dialog box.

            if (SUCCEEDED(hr))

            {

                CComPtr<IShellItem> pItem;

                hr = pFileOpen->GetResult(&pItem);

                if (SUCCEEDED(hr))

                {

                    PWSTR pszFilePath;

                    hr = pItem->GetDisplayName(SIGDN_FILESYSPATH, &pszFilePath);

                    // Display the file name to the user.

                    if (SUCCEEDED(hr))

                    {

                        MessageBox(NULL, pszFilePath, L"File Path", MB_OK);

                        CoTaskMemFree(pszFilePath);

                    }

                }

                // pItem goes out of scope.

            }

            // pFileOpen goes out of scope.

        }

        CoUninitialize();

    }

    return 0;

}

CVehicle* pVehicle = GetCurrentVehicle();

// Validate pointer

if(pVehicle==NULL) // Using == operator to compare pointer with NULL

   return FALSE;

// Do something with the pointer

pVehicle->Run();

CVehicle* pVehicle = GetCurrentVehicle();

// Validate pointer

if(pVehicle=NULL) // Oops! A mistyping here!

return FALSE;

// Do something with the pointer

pVehicle->Run(); // Crash!!!