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

CGAL 4.8 - 2D Triangulation

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CGAL::Triangulation_cw_ccw_2 Class Reference
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`#include <CGAL/Triangulation_2.h>`

Inherited by CGAL::Triangulation_2< Traits, Tds >, and CGAL::Triangulation_2< Weighted_point_mapper_2< Traits >, Tds >.

## Definition

The class `Triangulation_cw_ccw_2` offers two functions `int cw(int i)` and `int ccw(int i)` which, given the index of a vertex in a face, compute the index of the next vertex of the same face in clockwise or counterclockwise order.

This works also for neighbor indexes. Thus, for example the neighbor `neighbor(cw(i))` of a face `f` is the neighbor which is next to `neighbor(i)` turning clockwise around `f`. The face `neighbor(cw(i))` is also the first face encountered after `f` when turning clockwise around vertex `i` of `f`.

Many of the classes in the triangulation package inherit from `Triangulation_cw_ccw_2`. This is for instance the case for `CGAL::Triangulation_2::Face`. Thus, for example the neighbor `neighbor(cw(i))` of a face `f` is the neighbor which is next to `neighbor(i)` turning clockwise around `f`. The face `neighbor(cw(i))` is also the first face encountered after `f` when turning clockwise around vertex `i` of `f`.

Vertices and neighbors.

See Also
  `CGAL::Triangulation_2`
  `TriangulationDSFaceBase_2`

## Creation
| Triangulation_cw_ccw_2 ()
| default constructor.

## Operations
int | ccw (const int i) const
| returns the index of the neighbor or vertex that is next to the neighbor or vertex with index `i` in counterclockwise order around a face.
int | cw (const int i) const
| returns the index of the neighbor or vertex that is next to the neighbor or vertex with index `i` in counterclockwise order around a face.