ceph/src/boost/libs/multi_index/example/sequenced.cpp

   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
  27 using boost::multi_index_container;
  28 using namespace boost::multi_index;
  29
  30 /* text_container holds words as inserted and also keep them indexed
  31  * by dictionary order.
  32  */
  33
  34 typedef 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
  44 typedef nth_index<text_container,1>::type ordered_text;
  45
  46 typedef boost::tokenizer<boost::char_separator<char> > text_tokenizer;
  47
  48 int 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(tok.begin(),tok.end(),std::back_inserter(tc));
  62
  63   /* list all words in alphabetical order along with their number
  64    * of occurrences
  65    */
  66
  67   ordered_text& ot=get<1>(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(*it); /* jump to next   */
  71     std::cout<<std::right<<std::setw(3)   /* and compute the distance */
  72              <<std::distance(it,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     tc.begin(),tc.end(),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(common_words[n]);
  93   }
  94   std::cout<<std::endl;
  95   std::copy(
  96     tc.begin(),tc.end(),std::ostream_iterator<std::string>(std::cout," "));
  97   std::cout<<std::endl;
  98
  99   return 0;
 100 }