1/* Boost.MultiIndex example of use of sequenced indices.
2 *
3 * Copyright 2003-2008 Joaquin M Lopez Munoz.
4 * Distributed under the Boost Software License, Version 1.0.
5 * (See accompanying file LICENSE_1_0.txt or copy at
6 * http://www.boost.org/LICENSE_1_0.txt)
7 *
8 * See http://www.boost.org/libs/multi_index for library home page.
9 */
10
11#if !defined(NDEBUG)
12#define BOOST_MULTI_INDEX_ENABLE_INVARIANT_CHECKING
13#define BOOST_MULTI_INDEX_ENABLE_SAFE_MODE
14#endif
15
16#include <boost/multi_index_container.hpp>
17#include <boost/multi_index/identity.hpp>
18#include <boost/multi_index/ordered_index.hpp>
19#include <boost/multi_index/sequenced_index.hpp>
20#include <boost/tokenizer.hpp>
21#include <algorithm>
22#include <iomanip>
23#include <iostream>
24#include <iterator>
25#include <string>
26
27using boost::multi_index_container;
28using namespace boost::multi_index;
29
30/* text_container holds words as inserted and also keep them indexed
31 * by dictionary order.
32 */
33
34typedef multi_index_container<
35 std::string,
36 indexed_by<
37 sequenced<>,
38 ordered_non_unique<identity<std::string> >
39 >
40> text_container;
41
42/* ordered index */
43
44typedef nth_index<text_container,1>::type ordered_text;
45
46typedef boost::tokenizer<boost::char_separator<char> > text_tokenizer;
47
48int main()
49{
50 std::string text=
51 "Alice was beginning to get very tired of sitting by her sister on the "
52 "bank, and of having nothing to do: once or twice she had peeped into the "
53 "book her sister was reading, but it had no pictures or conversations in "
54 "it, 'and what is the use of a book,' thought Alice 'without pictures or "
55 "conversation?'";
56
57 /* feed the text into the container */
58
59 text_container tc;
60 text_tokenizer tok(text,boost::char_separator<char>(" \t\n.,;:!?'\"-"));
61 std::copy(first: tok.begin(),last: tok.end(),result: std::back_inserter(x&: tc));
62
63 /* list all words in alphabetical order along with their number
64 * of occurrences
65 */
66
67 ordered_text& ot=get<1>(m&: tc);
68 for(ordered_text::iterator it=ot.begin();it!=ot.end();){
69 std::cout<<std::left<<std::setw(14)<<*it<<":"; /* print the word */
70 ordered_text::iterator it2=ot.upper_bound(x: *it); /* jump to next */
71 std::cout<<std::right<<std::setw(3) /* and compute the distance */
72 <<std::distance(first: it,last: it2)<<" times"<<std::endl;
73 it=it2;
74 }
75
76 /* reverse the text and print it out */
77
78 tc.reverse();
79 std::cout<<std::endl;
80 std::copy(
81 first: tc.begin(),last: tc.end(),result: std::ostream_iterator<std::string>(std::cout," "));
82 std::cout<<std::endl;
83 tc.reverse(); /* undo */
84
85 /* delete most common English words and print the result */
86
87 std::string common_words[]=
88 {"the","of","and","a","to","in","is","you","that","it",
89 "he","for","was","on","are","as","with","his","they","at"};
90
91 for(std::size_t n=0;n<sizeof(common_words)/sizeof(common_words[0]);++n){
92 ot.erase(x: common_words[n]);
93 }
94 std::cout<<std::endl;
95 std::copy(
96 first: tc.begin(),last: tc.end(),result: std::ostream_iterator<std::string>(std::cout," "));
97 std::cout<<std::endl;
98
99 return 0;
100}
101

source code of boost/libs/multi_index/example/sequenced.cpp