## CGAL::Arrangement_2<Dcel,Traits,Base_node>::Halfedge

### Definition

An object e of the class Halfedge inherits the halfedge of the planar map induced by the arrangement. It has the additional method edge_node() which returns an iterator to the edge node in the hierarchy tree, and overlap_edges() which returns a circulator over the overlapping edge nodes that correspond to e.

### Operations

Edge_iterator

e.edge_node ()

returns an iterator to the edge node in the hierarchy tree which holds the curve from which the halfedge was generated. This enables traversal over the hierarchy tree that e belongs to. For example, if eit is the returned iterator, eit->curve_node() will return the root of the hierarchy tree and ++eit will return the following edge in the hierarchy tree (unless eit is the rightmost edge in the hierarchy tree, in which case ++eit will return the past-the-end value.)

Overlap_circulator | e.overlap_edges () | returns a bidirectional circulator to traverse all edge nodes that correspond to e.