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/Src/Dependencies/Boost/libs/iterator/example/permutation_iter_example.cpp

http://hadesmem.googlecode.com/
C++ | 68 lines | 49 code | 15 blank | 4 comment | 9 complexity | 97b9f44e82179239c52edb78f6aee35d MD5 | raw file
 1// Copyright (C) 2004 Jeremy Siek <jsiek@cs.indiana.edu>
 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 <iostream>
 7#include <vector>
 8#include <deque>
 9#include <algorithm>
10#include <boost/iterator/permutation_iterator.hpp>
11#include <boost/cstdlib.hpp>
12#include <assert.h>
13
14
15int main() {
16  using namespace boost;
17  int i = 0;
18
19  typedef std::vector< int > element_range_type;
20  typedef std::deque< int > index_type;
21
22  static const int element_range_size = 10;
23  static const int index_size = 4;
24
25  element_range_type elements( element_range_size );
26  for(element_range_type::iterator el_it = elements.begin() ; el_it != elements.end() ; ++el_it)
27    *el_it = std::distance(elements.begin(), el_it);
28
29  index_type indices( index_size );
30  for(index_type::iterator i_it = indices.begin() ; i_it != indices.end() ; ++i_it ) 
31    *i_it = element_range_size - index_size + std::distance(indices.begin(), i_it);
32  std::reverse( indices.begin(), indices.end() );
33
34  typedef permutation_iterator< element_range_type::iterator, index_type::iterator > permutation_type;
35  permutation_type begin = make_permutation_iterator( elements.begin(), indices.begin() );
36  permutation_type it = begin;
37  permutation_type end = make_permutation_iterator( elements.begin(), indices.end() );
38
39  std::cout << "The original range is : ";
40  std::copy( elements.begin(), elements.end(), std::ostream_iterator< int >( std::cout, " " ) );
41  std::cout << "\n";
42
43  std::cout << "The reindexing scheme is : ";
44  std::copy( indices.begin(), indices.end(), std::ostream_iterator< int >( std::cout, " " ) );
45  std::cout << "\n";
46
47  std::cout << "The permutated range is : ";
48  std::copy( begin, end, std::ostream_iterator< int >( std::cout, " " ) );
49  std::cout << "\n";
50
51  std::cout << "Elements at even indices in the permutation : ";
52  it = begin;
53  for(i = 0; i < index_size / 2 ; ++i, it+=2 ) std::cout << *it << " ";
54  std::cout << "\n";
55
56  std::cout << "Permutation backwards : ";
57  it = begin + (index_size);
58  assert( it != begin );
59  for( ; it-- != begin ; ) std::cout << *it << " ";
60  std::cout << "\n";
61
62  std::cout << "Iterate backward with stride 2 : ";
63  it = begin + (index_size - 1);
64  for(i = 0 ; i < index_size / 2 ; ++i, it-=2 ) std::cout << *it << " ";
65  std::cout << "\n";
66
67  return boost::exit_success;
68}