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.


Circulator_from_container<C> c;
a circulator c on an empty sequence.

Circulator_from_container<C> c ( C* container);
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.

Circulator_from_container<C> c ( C* container, C::iterator i);
a circulator c initialized to refer to the element *i in container.
Precondition: *i is dereferenceable and refers to container.


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.

See Also

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 <CGAL/basic.h>
#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;
    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;