# Boost.Range

## Range Adaptors

#### `map_values`

>     rng | boost::adaptors::map_values

>     boost::make_map_value_range( rng )

- Precondition: The value-type of the range is an instantiation of std::pair.
- Postcondition: For all elements `x` in the returned range, `x` is the result of `y.second` where `y` is the corresponding element in the original range.
- Range Category: SinglePassRange

### 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_values,
                    std::ostream_iterator<int>(std::cout, ","));

                return 0;
            }

This produces the output:
`0,10,20,30,40,50,60,70,80,90`

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