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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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