ceph/src/boost/libs/iterator/doc/counting_iterator_eg.rst

   1 .. Copyright David Abrahams 2006. Distributed under the Boost
   2 .. Software License, Version 1.0. (See accompanying
   3 .. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   4
   5 Example
   6 .......
   7
   8 This example fills an array with numbers and a second array with
   9 pointers into the first array, using ``counting_iterator`` for both
  10 tasks. Finally ``indirect_iterator`` is used to print out the numbers
  11 into the first array via indirection through the second array.
  12
  13 ::
  14
  15     int N = 7;
  16     std::vector<int> numbers;
  17     typedef std::vector<int>::iterator n_iter;
  18     std::copy(boost::counting_iterator<int>(0),
  19              boost::counting_iterator<int>(N),
  20              std::back_inserter(numbers));
  21
  22     std::vector<std::vector<int>::iterator> pointers;
  23     std::copy(boost::make_counting_iterator(numbers.begin()),
  24               boost::make_counting_iterator(numbers.end()),
  25               std::back_inserter(pointers));
  26
  27     std::cout << "indirectly printing out the numbers from 0 to "
  28               << N << std::endl;
  29     std::copy(boost::make_indirect_iterator(pointers.begin()),
  30               boost::make_indirect_iterator(pointers.end()),
  31               std::ostream_iterator<int>(std::cout, " "));
  32     std::cout << std::endl;
  33
  34
  35 The output is::
  36
  37     indirectly printing out the numbers from 0 to 7
  38     0 1 2 3 4 5 6
  39
  40 The source code for this example can be found `here`__.
  41
  42 __ ../example/counting_iterator_example.cpp
  43