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:: 6 7 using namespace boost; 8 int i = 0; 9 10 typedef std::vector< int > element_range_type; 11 typedef std::list< int > index_type; 12 13 static const int element_range_size = 10; 14 static const int index_size = 4; 15 16 element_range_type elements( element_range_size ); 17 for(element_range_type::iterator el_it = elements.begin() ; el_it != elements.end() ; ++el_it) 18 *el_it = std::distance(elements.begin(), el_it); 19 20 index_type indices( index_size ); 21 for(index_type::iterator i_it = indices.begin() ; i_it != indices.end() ; ++i_it ) 22 *i_it = element_range_size - index_size + std::distance(indices.begin(), i_it); 23 std::reverse( indices.begin(), indices.end() ); 24 25 typedef permutation_iterator< element_range_type::iterator, index_type::iterator > permutation_type; 26 permutation_type begin = make_permutation_iterator( elements.begin(), indices.begin() ); 27 permutation_type it = begin; 28 permutation_type end = make_permutation_iterator( elements.begin(), indices.end() ); 29 30 std::cout << "The original range is : "; 31 std::copy( elements.begin(), elements.end(), std::ostream_iterator< int >( std::cout, " " ) ); 32 std::cout << "\n"; 33 34 std::cout << "The reindexing scheme is : "; 35 std::copy( indices.begin(), indices.end(), std::ostream_iterator< int >( std::cout, " " ) ); 36 std::cout << "\n"; 37 38 std::cout << "The permutated range is : "; 39 std::copy( begin, end, std::ostream_iterator< int >( std::cout, " " ) ); 40 std::cout << "\n"; 41 42 std::cout << "Elements at even indices in the permutation : "; 43 it = begin; 44 for(i = 0; i < index_size / 2 ; ++i, it+=2 ) std::cout << *it << " "; 45 std::cout << "\n"; 46 47 std::cout << "Permutation backwards : "; 48 it = begin + (index_size); 49 assert( it != begin ); 50 for( ; it-- != begin ; ) std::cout << *it << " "; 51 std::cout << "\n"; 52 53 std::cout << "Iterate backward with stride 2 : "; 54 it = begin + (index_size - 1); 55 for(i = 0 ; i < index_size / 2 ; ++i, it-=2 ) std::cout << *it << " "; 56 std::cout << "\n"; 57 58 59The output is:: 60 61 The original range is : 0 1 2 3 4 5 6 7 8 9 62 The reindexing scheme is : 9 8 7 6 63 The permutated range is : 9 8 7 6 64 Elements at even indices in the permutation : 9 7 65 Permutation backwards : 6 7 8 9 66 Iterate backward with stride 2 : 6 8 67 68 69The source code for this example can be found `here`__. 70 71__ ../example/permutation_iter_example.cpp 72