#include <sstream>
#include <boost/serialization/map.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>

std::ostream& operator<<(std::ostream& out, const std::multimap<int, double> &o)
{
	for (auto &i : o)
		out << "(" << i.first << ", " << i.second << ")\n";

	return out;
}

int main()
{
	std::multimap<int, double> o;
	o.insert(std::make_pair(1, 1.1));
	o.insert(std::make_pair(1, 1.2));
	o.insert(std::make_pair(2, 2.1));
	o.insert(std::make_pair(2, 2.2));

	std::stringstream sstr;
	boost::archive::text_oarchive(sstr) << o;
	std::cout << o << std::endl;

	std::cout << sstr.str() << std::endl;

	std::multimap<int, double> i;
	boost::archive::text_iarchive(sstr) >> i;
	std::cout << i << std::endl;
}