Re: [Boost-users] std::accumulate with condition?

On Tue, Sep 22, 2009 at 3:11 PM, Archie14 wrote:

If a given class defines operator + and there is a vector of instances of that class: how I can use std::accumulate to count sum against this vector for the elements that satisfy certain conditions? class A { public: A(useinsum) : _useinsum(useinsum) {}; bool useinsum() {return _useinsum;} int operator + (int a) {return _i + a;} private bool _useinsum; int _i; }

std::vector<A> lst;

will that work? std::accumulate(lst.begin(), lst.end(), 0, boost::lambda::bind(&A::useinsum, boost::lambda::_1) == false)

Would filter iterators help you out? http://www.boost.org/doc/libs/1_40_0/libs/iterator/doc/filter_iterator.html - Rob.