[Boost-users] [Min-Max] Usage with a member function as criteria.

Hello Boost users, I'm working on my thesis with the Boost library (Boost-1.34.1) running on g++ (GCC) 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2). What I'm trying to do can be done very simply, but I preferred to do it more appropriately, I believe, using the Boost Min-Max library. I'm trying to simultaneously obtain the maximum and minimum values of a member function call over a lists of objects. Suppose there exists a class utl::Particle; with a member function double GetEnergy() const; In a member field of another class I have a list of those particles std::listutl::Particle particles; for which I want min/max GetEnergy() values. How is that accomplished using Boost.Min-Max? Below I give some excerpts of some of the things I've tried, but didn't work. In order to try to understand what I was doing I split the code over several lines, so to minimize the non-compiling one. In both cases the error seems to be (that line is what I believe to be the most important part of all the error messages): boost/iterator/iterator_adaptor.hpp:353: error: no match for 'operator-' in... First attempt: boost::function energy = boost::lambda::bind(&utl::Particle::GetEnergy, boost::lambda::_1 ); boost::transform_iterator< boost::function , listutl::Particle::const_iterator> itBeg(particles.begin(), energy),itEnd(particles.end(), energy); boost::minmax(itBeg, itEnd); // This call doesn't compile. Second attempt: boost::function energy = boost::lambda::bind(&utl::Particle::GetEnergy, boost::lambda::_1 ); // As in the first case. boost::minmax( boost::make_transform_iterator(particles.begin(),energy ), boost::make_transform_iterator(particles.end() ,energy )); // This call doesn't compile. Thanks a lot for your help. -- Rodolfo Federico Gamarra