ceph/src/boost/libs/iterator/example/indirect_iterator_example.cpp

   1 // (C) Copyright Jeremy Siek 2000-2004.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #include <boost/config.hpp>
   7 #include <vector>
   8 #include <iostream>
   9 #include <iterator>
  10 #include <functional>
  11 #include <algorithm>
  12 #include <boost/bind/bind.hpp>
  13 #include <boost/iterator/indirect_iterator.hpp>
  14
  15 int main(int, char*[])
  16 {
  17   char characters[] = "abcdefg";
  18   const int N = sizeof(characters)/sizeof(char) - 1; // -1 since characters has a null char
  19   char* pointers_to_chars[N];                        // at the end.
  20   for (int i = 0; i < N; ++i)
  21     pointers_to_chars[i] = &characters[i];
  22
  23   // Example of using indirect_iterator
  24
  25   boost::indirect_iterator<char**, char>
  26     indirect_first(pointers_to_chars), indirect_last(pointers_to_chars + N);
  27
  28   std::copy(indirect_first, indirect_last, std::ostream_iterator<char>(std::cout, ","));
  29   std::cout << std::endl;
  30
  31
  32   // Example of making mutable and constant indirect iterators
  33
  34   char mutable_characters[N];
  35   char* pointers_to_mutable_chars[N];
  36   for (int j = 0; j < N; ++j)
  37     pointers_to_mutable_chars[j] = &mutable_characters[j];
  38
  39   boost::indirect_iterator<char* const*> mutable_indirect_first(pointers_to_mutable_chars),
  40     mutable_indirect_last(pointers_to_mutable_chars + N);
  41   boost::indirect_iterator<char* const*, char const> const_indirect_first(pointers_to_chars),
  42     const_indirect_last(pointers_to_chars + N);
  43
  44   std::transform(const_indirect_first, const_indirect_last,
  45                  mutable_indirect_first, boost::bind(std::plus<char>(), 1, boost::placeholders::_1));
  46
  47   std::copy(mutable_indirect_first, mutable_indirect_last,
  48             std::ostream_iterator<char>(std::cout, ","));
  49   std::cout << std::endl;
  50
  51
  52   // Example of using make_indirect_iterator()
  53
  54   std::copy(boost::make_indirect_iterator(pointers_to_chars),
  55             boost::make_indirect_iterator(pointers_to_chars + N),
  56             std::ostream_iterator<char>(std::cout, ","));
  57   std::cout << std::endl;
  58
  59   return 0;
  60 }