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Boost.Range |
map_keysrng | boost::adaptors::map_keysboost::make_map_key_range( rng )
x in the returned range,
x is the result of y.first where
y is the corresponding element in the original range.
#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