Version 5.0 The LEDA User Manual

13.16 Node Attribute Accessors ( node attribute da
)
1. Definition
An instance da of class node attribute da manages the access to a node parameter
with type T of a parameterized graph GRAPH.
Classes edge attribute da is defined completely analogously.
#include < LEDA/graph/graph iterator.h >
2. Creation
node attribute da da;
introduces a variable da of this class.
3. Operations
T
void
get(const node attribute da& ma, const Iter& it)
returns the associated value of it for this accessor.
set(node attribute da& ma, const Iter& it, T val)
sets the associated value of it for this accessor to the
given value.
4. Implementation
Constant Overhead.
5. Example
Given a parameterized graph G with nodes associated with colours, we want to count the
number of red nodes. Since we have the template function of sect. 13.13 we can easily use
it to do the computation:
int count_red(GRAPH G) {
node_attribute_da Color;
return count_red_t(G,Color); }