Version 5.0 The LEDA User Manual

4. Implementation
Constant Overhead.
5. Example
We count the number of ’red nodes’ in a parameterized graph G.
int count_red(graph G, node_array COL) {
node_array_da Color(COL);
int counter=0;
NodeIt it(G);
while (it.valid()) {
if (get(Color,it)==red) counter++;
it++; }
return counter;
}
Suppose we want to make this ’algorithm’ flexible in the representation of colors. Then
we could write this version:
template
int count_red_t(graph G, DA Color) {
int counter=0;
NodeIt it(G);
while (it.valid()) {
if (get(Color,it)==red) counter++;
it++; }
return counter;
}
With the templatized version it is easily to customize it to match the interface of the
version:
int count_red(graph G, node_array COL) {
node_array_da Color(COL);
return count_red_t(G,Color); }