#include <boost/multi_index_container.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/identity.hpp>
#include <boost/multi_index/member.hpp>
#include <string>

typedef boost::multi_index_container<
  int,
  boost::multi_index::indexed_by<
    boost::multi_index::hashed_unique<
      boost::multi_index::identity<int>
    >
  >
> int_unordered_set;

struct istr_pair
{
  istr_pair(int i,const std::string& str):first(i),second(str){}

  int                 first;
  mutable std::string second;
};

typedef boost::multi_index_container<
  istr_pair,
  boost::multi_index::indexed_by<
    boost::multi_index::hashed_unique<
      boost::multi_index::member<istr_pair,int,&istr_pair::first>
    >
  >
> istr_unordered_map;

int main()
{
  int_unordered_set ius;
  ius.insert(1);
  ius.insert(2);
  ius.find(3);

  istr_unordered_map isum;

  isum.insert(istr_pair(1,"hola"));
  isum.insert(istr_pair(2,"adios"));
  isum.find(2)->second="taluego";
}