\( \newcommand{\E}{\mathrm{E}} \) \( \newcommand{\A}{\mathrm{A}} \) \( \newcommand{\R}{\mathrm{R}} \) \( \newcommand{\N}{\mathrm{N}} \) \( \newcommand{\Q}{\mathrm{Q}} \) \( \newcommand{\Z}{\mathrm{Z}} \) \( \def\ccSum #1#2#3{ \sum_{#1}^{#2}{#3} } \def\ccProd #1#2#3{ \sum_{#1}^{#2}{#3} }\)

CGAL 4.3 - Handles and Circulators

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CGAL::Circulator_from_iterator< I > Class Template Reference
Adapters for Iterators and Containers

`#include <CGAL/circulator.h>`

## Definition

The adaptor `Circulator_from_iterator` converts two iterators of type `I`, a begin and a past-the-end value, to a circulator of equal category.

The iterator must be at least of the forward iterator category. The circulator will be mutable or non-mutable according to the iterator. Iterators provide no `size_type`. This adapter assumes `std::size_t` instead.

Operations

The adaptor conforms to the requirements of the respective 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_container`
  `Circulator`

Example

The following program composes two adaptors - from an iterator to a circulator and back to an iterator. It applies an STL sort algorithm on a STL vector containing 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 Circulator/circulator_prog1.cpp

#include <CGAL/basic.h>
#include <cassert>
#include <vector>
#include <algorithm>
#include <CGAL/circulator.h>
typedef std::vector<int>::iterator I;
typedef CGAL::Circulator_from_iterator<I> 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.begin(), v.end());
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;
}

Another example usage for this adaptor is a random access circulator over the built-in C arrays. Given an array of type `T*` with a begin pointer `b` and a past-the-end pointer `e` the adaptor `Circulator_from_iterator<T*> c(b,e)` is a random access circulator `c` over this array.

Examples:
  Circulator/circulator_prog1.cpp.

## Types
In addition all types required for circulators are provided.
typedef I | iterator

## Creation
| Circulator_from_iterator ()
| a circulator `c` on an empty sequence.
| Circulator_from_iterator (const I &begin, const I &end, const I &cur=begin)
| a circulator `c` initialized to refer to the element `*cur` in a range `[begin, end)`. More...
| Circulator_from_iterator (const Circulator_from_iterator< I, T, Size, Dist > &d, const I &cur)
| a copy of circulator `d` referring to the element `*cur`. More...

## Constructor & Destructor Documentation

template<typename I>

CGAL::Circulator_from_iterator< I >::Circulator_from_iterator | ( | const I & | begin,
|  | const I & | end,
|  | const I & | cur = `begin`
| ) |  |

a circulator `c` initialized to refer to the element `*cur` in a range `[begin, end)`.

The circulator `c` refers to a empty sequence if `begin==end`.

template<typename I>

CGAL::Circulator_from_iterator< I >::Circulator_from_iterator | ( | const Circulator_from_iterator< I, T, Size, Dist > & | d,
|  | const I & | cur
| ) |  |

a copy of circulator `d` referring to the element `*cur`.

The circulator `c` refers to a empty sequence if `d` does so.