[Boost-users] Annoying coding

Hi again, I have a problem. Not really big one but annoying. Often we need to write code like this: struct A{ int a; std::string b; }; int a_sum(int i, const A &v){ return v.a + i; }; std::vector<A> v; //fill this vector somewhere std::accumulate( v.begin(), v.end(), 0, a_sum ); or something like int m_sum(int i, const std::pair p) { return p.first + i; }; std::map m; std::accumlate( m.begin(), m.end(), 0, m_sum); Or in common words we need to write some kind functor which just get member from element and apply it to another functor. Of course I can write something like: template struct get_mem{ const V_ &operator()(const T_ &elem){ return elem->*Ptr_; }; }; but may be there is library way to do this?