int Translate(const apvector<bool> & info, int index)
// precondition: info contains info.length() entries,
//               0 <= index < info.length() - 2
{
    int sum = 0;
    if (info[index])
    {
        sum += 4;
    }
    if (info[index+1])
    {
        sum += 2;
    }
    if (info[index+2])
    {
        sum += 1;
    }
    return sum;
}