int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
    int nRetCode = 0;

    // initialize MFC and print and error on failure
    if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))
    {
        // TODO: change error code to suit your needs
        _tprintf(_T("Fatal Error: MFC initialization failed\n"));
        nRetCode = 1;
    }
    else
    {
        // TODO: code your application's behavior here.
        CFile file(_T("\\VC教程\\SIO.txt"),CFile::modeReadWrite);
        DWORD m_nLen=file.GetLength();
        char str[80];
        file.Read(&str,m_nLen);
        for(int i=0;i<m_nLen;i++)
            cout<<str[i];
        cout<<endl;
        file.Close();
    }

    return nRetCode;
}
程序运行完出现一个黑底色的对话框，显示出SIO文档的字符串。但是瞬间就没了，怎么让它长时间显示？