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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 | ||
15 | int 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 ); | |
f67539c2 | 30 | for(index_type::iterator i_it = indices.begin() ; i_it != indices.end() ; ++i_it ) |
7c673cae FG |
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 | } |