#include <boost/fusion/adapted/std_pair.hpp>
#include <boost/fusion/include/std_pair.hpp>
        Model
            Random
            Access Sequence
        Example
std::pair<int, std::string> p(123, "Hola!!!");
std::cout << at_c<0>(p) << std::endl;
std::cout << at_c<1>(p) << std::endl;
std::cout << p << std::endl;
        std::pair,
        and std::pair
      Dan Marsden, Tobias Schwinger

        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)