## TriangulationDataStructure_3::Vertex

### Definition

The concept TriangulationDataStructure_3::Vertex represents the vertex class of a 3D-triangulation data structure. It must define the types and operations listed in this section. Some of these requirements are of geometric nature, they are optional when using the triangulation data structure class alone. They become compulsory when the triangulation data structure is used as a layer for the geometric triangulation class. (See Section .)

### Types

TriangulationDataStructure_3::Vertex::Point
| Optional for the triangulation data structure alone.

The class TriangulationDataStructure_3::Vertex defines types that are the same as some of the types defined by the triangulation data structure class TriangulationDataStructure_3.

typedef TriangulationDataStructure_3
| Triangulation_data_structure;
typedef TriangulationDataStructure_3::Vertex_handle
| Vertex_handle;
typedef TriangulationDataStructure_3::Cell_handle
| Cell_handle;

### Creation

In order to obtain new vertices or destruct unused vertices, the user must call the create_vertex() and delete_vertex() methods of the triangulation data structure.

### Operations

### Access Functions

Cell_handle | v.cell () | Returns a cell of the triangulation having v as vertex.

### Setting

void | v.set_cell ( Cell_handle c)
|  | Sets the incident cell to c.
void | v.set_point ( Point p)
|  | Sets the point to p. Optional for the triangulation data structure alone.

### Checking

bool | v.is_valid ( bool verbose = false)
|  | Checks the validity of the vertex. Must check that its incident cell has this vertex. The validity of the base vertex is also checked. When verbose is set to true, messages are printed to give a precise indication on the kind of invalidity encountered.

### See Also

TriangulationDataStructure_3::Cell.