ceph/src/boost/libs/iterator/example/counting_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
   7 #include <boost/config.hpp>
   8 #include <algorithm>
   9 #include <iostream>
  10 #include <iterator>
  11 #include <vector>
  12 #include <boost/iterator/counting_iterator.hpp>
  13 #include <boost/iterator/indirect_iterator.hpp>
  14 #include <boost/cstdlib.hpp>
  15
  16 int main(int, char*[])
  17 {
  18   // Example of using counting_iterator
  19   std::cout << "counting from 0 to 4:" << std::endl;
  20   boost::counting_iterator<int> first(0), last(4);
  21   std::copy(first, last, std::ostream_iterator<int>(std::cout, " "));
  22   std::cout << std::endl;
  23
  24   // Example of using counting iterator to create an array of pointers.
  25   int N = 7;
  26   std::vector<int> numbers;
  27   typedef std::vector<int>::iterator n_iter;
  28   // Fill "numbers" array with [0,N)
  29   std::copy(
  30       boost::counting_iterator<int>(0)
  31       , boost::counting_iterator<int>(N)
  32       , std::back_inserter(numbers));
  33
  34   std::vector<std::vector<int>::iterator> pointers;
  35
  36   // Use counting iterator to fill in the array of pointers.
  37   // causes an ICE with MSVC6
  38   std::copy(boost::make_counting_iterator(numbers.begin()),
  39             boost::make_counting_iterator(numbers.end()),
  40             std::back_inserter(pointers));
  41
  42   // Use indirect iterator to print out numbers by accessing
  43   // them through the array of pointers.
  44   std::cout << "indirectly printing out the numbers from 0 to "
  45             << N << std::endl;
  46   std::copy(boost::make_indirect_iterator(pointers.begin()),
  47             boost::make_indirect_iterator(pointers.end()),
  48             std::ostream_iterator<int>(std::cout, " "));
  49   std::cout << std::endl;
  50
  51   return boost::exit_success;
  52 }