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// Boost.Bimap
//
// Copyright (c) 2006-2007 Matias Capeletto
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// Boost.Bimap Example
//-----------------------------------------------------------------------------
// Hashed indices can be used as an alternative to ordered indices when fast
// lookup is needed and sorting information is of no interest. The example
// features a word counter where duplicate entries are checked by means of a
// hashed index.
#include <boost/config.hpp>
//[ code_mi_to_b_path_hashed_indices
#include <iostream>
#include <iomanip>
#include <boost/tokenizer.hpp>
#include <boost/bimap/bimap.hpp>
#include <boost/bimap/unordered_set_of.hpp>
#include <boost/bimap/multiset_of.hpp>
#include <boost/bimap/support/lambda.hpp>
using namespace boost::bimaps;
struct word {};
struct occurrences {};
typedef bimap
<
multiset_of< tagged<unsigned int,occurrences>, std::greater<unsigned int> >,
unordered_set_of< tagged< std::string, word> >
> word_counter;
typedef boost::tokenizer<boost::char_separator<char> > text_tokenizer;
int main()
{
std::string text=
"Relations between data in the STL are represented with maps."
"A map is a directed relation, by using it you are representing "
"a mapping. In this directed relation, the first type is related to "
"the second type but it is not true that the inverse relationship "
"holds. This is useful in a lot of situations, but there are some "
"relationships that are bidirectional by nature.";
// feed the text into the container
word_counter wc;
text_tokenizer tok(text,boost::char_separator<char>(" \t\n.,;:!?'\"-"));
unsigned int total_occurrences = 0;
for( text_tokenizer::const_iterator it = tok.begin(), it_end = tok.end();
it != it_end ; ++it )
{
++total_occurrences;
word_counter::map_by<occurrences>::iterator wit =
wc.by<occurrences>().insert(
word_counter::map_by<occurrences>::value_type(0,*it)
).first;
wc.by<occurrences>().modify_key( wit, ++_key);
}
// list words by frequency of appearance
std::cout << std::fixed << std::setprecision(2);
for( word_counter::map_by<occurrences>::const_iterator
wit = wc.by<occurrences>().begin(),
wit_end = wc.by<occurrences>().end();
wit != wit_end; ++wit )
{
std::cout << std::setw(15) << wit->get<word>() << ": "
<< std::setw(5)
<< 100.0 * wit->get<occurrences>() / total_occurrences << "%"
<< std::endl;
}
return 0;
}
//]
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