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