// 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; } //]