Boost.Range

Range Adaptors


map_keys

rng | boost::adaptors::map_keys
boost::make_map_key_range( rng )

Example

        #include <boost/range/adaptor/map.hpp>
        #include <boost/range/algorithm/copy.hpp>
        #include <boost/assign.hpp>
        #include <algorithm>
        #include <iostream>
        #include <map>
        #include <vector>
        
        int main(int argc, const char* argv[])
        {
            using namespace boost::assign;
            using namespace boost::adaptors;
            
            std::map<int,int> input;
            for (int i = 0; i < 10; ++i)
                input.insert(std::make_pair(i, i * 10));
                
            boost::copy(
                input | map_keys,
                std::ostream_iterator<int>(std::cout, ","));
                
            return 0;
        }
    

This produces the output:
0,1,2,3,4,5,6,7,8,9


(C) Copyright Neil Groves 2009 (C) Copyright Thorsten Ottosen 2003-2004