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

### Definition

An object cn of the class Curve_node is a node holding the curve in the hierarchy tree, corresponding to a root of a hierarchy. It holds the original curve inserted into the arrangement.

### Inherits From

Subcurve_node

In addition to the operations of Subcurve_node the following operations are implemented.

### Operations

bool | cn.is_edge_node () | returns false;
Subcurve_iterator | cn.level_begin ( unsigned int i)
|  | returns the begin iterator to the i'th level of subcurves (for the first subcurve level i=0). Precondition: i < cn.number_of_sc_levels()
Subcurve_iterator | cn.level_end ( unsigned int i)
|  | returns the past-the-end iterator to the i'th level of subcurves (for the first subcurve level i=0). Precondition: i < cn.number_of_sc_levels()
unsigned int | cn.number_of_sc_levels ()
|  | returns the number of subcurve levels (not including the edge level and the curve level).
Edge_iterator | cn.edges_begin () | overrides the same function in the Subcurve_node, to gain efficiency.
Edge_iterator | cn.edges_end () | overrides the same function in the Subcurve_node, to gain efficiency.