graph_traits<Graph>
Just like the
iterators of STL, graphs have associated types. As stated
in the various graph concepts, a
graph has quite a few associated types: vertex_descriptor,
edge_descriptor, out_edge_iterator, etc.. Any
particular graph concepts will not require that all of the following
associated types be defined. When implementing a graph class that
fullfils one or more graph concepts, for associated types that are not
required by the concepts, it is ok to use void as the type
(when using nested typedefs inside the graph class), or to leave the
typedef out of the graph_traits specialization for the graph
class.
template <typename Graph>
struct graph_traits {
typedef typename Graph::vertex_descriptor vertex_descriptor;
typedef typename Graph::edge_descriptor edge_descriptor;
typedef typename Graph::adjacency_iterator adjacency_iterator;
typedef typename Graph::out_edge_iterator out_edge_iterator;
typedef typename Graph::in_edge_iterator in_edge_iterator;
typedef typename Graph::vertex_iterator vertex_iterator;
typedef typename Graph::edge_iterator edge_iterator;
typedef typename Graph::directed_category directed_category;
typedef typename Graph::edge_parallel_category edge_parallel_category;
typedef typename Graph::traversal_category traversal_category;
typedef typename Graph::vertices_size_type vertices_size_type;
typedef typename Graph::edges_size_type edges_size_type;
typedef typename Graph::degree_size_type degree_size_type;
};
Where Defined
boost/graph/graph_traits.hpp
Template Parameters
Parameter | Description |
Graph |
The graph type whose associated types are being accessed.
|
Model of
DefaultConstructible and
Assignable
Type Requirements
Members
Member | Description |
vertex_descriptor
|
The type for the objects used to identity vertices in the graph.
|
edge_descriptor
|
The type for the objects used to identity edges in the graph.
|
adjacency_iterator
|
The type for the iterators that traverse the vertices adjacent
to a vertex.
|
out_edge_iterator
|
The type for the iterators that traverse through the out-edges
of a vertex.
|
in_edge_iterator
|
The type for the iterators that traverse through the in-edges
of a vertex.
|
vertex_iterator
|
The type for the iterators that traverse through the complete vertex
set of the graph.
|
edge_iterator
|
The type for the iterators that traverse through the complete edge
set of the graph.
|
directed_category
|
This says whether the graph is undirected (undirected_tag)
or directed (directed_tag).
|
edge_parallel_category
|
This says whether the graph allows parallel edges to be inserted
(allow_parallel_edge_tag) or if it automatically removes
parallel edges (disallow_parallel_edge_tag).
|
traversal_category
|
The ways in which the vertices in the graph can be traversed.
The traversal category tags are:
incidence_graph_tag, adjacency_graph_tag,
bidirectional_graph_tag, vertex_list_graph_tag,
edge_list_graph_tag, vertex_and_edge_list_graph_tag,
adjacency_matrix_tag. You can also create your own
tag which should inherit from one of the above.
|
vertices_size_type
|
The unsigned integer type used for representing the number of
vertices in the graph.
|
edge_size_type
|
The unsigned integer type used for representing the number of
edge in the graph.
|
degree_size_type
|
The unsigned integer type used for representing the degree
of vertices in the graph.
|
|