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The adaptor Circulator_from_container<C> provides a circulator for an STL container C of equal category as the iterator provided by the container. The iterator must be at least of the forward iterator category. The corresponding non-mutable circulator is called Const_circulator_from_container<C>.
The container type C is supposed to conform to the STL requirements for container (i.e. to have a begin() and an end() iterator as well as the local types reference, const_reference, value_type, size_type, and difference_type).
#include <CGAL/circulator.h>
All types required for circulators are provided.
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a circulator c on an empty sequence.
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a circulator c initialized to refer to the first element in
container, i.e. container.begin().
The circulator c refers to an empty sequence if the
container is empty.
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a circulator c initialized to refer to the element *i in
container.
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The adaptor conforms to the requirements of the corresponding circulator category. An additional member function current_iterator() returns the current iterator pointing to the same position as the circulator does.
Container_from_circulator, Circulator_from_iterator, Circulator.
The following program composes two adaptors - from a container to a circulator and back to an iterator. It applies an STL sort algorithm on a STL vector with three elements. The resulting vector will be [2 5 9] as it is checked by the assertions. The program is part of the Cgal distribution.
File: examples/Circulator/circulator_prog2.cpp
#include <cassert>
#include <vector>
#include <algorithm>
#include <CGAL/circulator.h>
typedef CGAL::Circulator_from_container< std::vector<int> > Circulator;
typedef CGAL::Container_from_circulator<Circulator> Container;
typedef Container::iterator Iterator;
int main() {
std::vector<int> v;
v.push_back(5);
v.push_back(2);
v.push_back(9);
Circulator c( &v);
Container container( c);
std::sort( container.begin(), container.end());
Iterator i = container.begin();
assert( *i == 2);
i++; assert( *i == 5);
i++; assert( *i == 9);
i++; assert( i == container.end());
return 0;
}