//in person.h
struct less_last_first_id
{
  bool operator()(person const &lh, person const &rh) const
    {return ((lh.last_ < rh.last_)?(true):
            ((lh.last_ > rh.last_)?(false):
            ((lh.first_ < rh.first_)?(true):
            ((lh.first_ > rh.first_)?(false):
            ((lh.id_ < rh.id_)?(true):
            ((lh.id_ > rh.id_)?(false):
            (false)))))));}
};

//usage
std::sort(people.begin(), people.end(), less_last_first_id());