I would like to do something like this

void Conditional(const bool show)
{
    unsigned int NumIters = 1e9;

    boost::progress_display show_progress;
    if(show)
        show_progress = boost::progress_display(NumIters);

    double temp;
    for(unsigned int i = 0; i < NumIters; i++)
    {
        temp = sin(i) / i;
        if(show)
            ++show_progress;
    }
}

It doesn't seem like I can instantiate a progress_display like this. Is there a way to conditionally have a progress display?

Thanks,
Dave