In order to traverse the graph, for each node we need the incoming and the outgoing links. Recall that for links we already have the corresponding information, i.e. the fromNodes and toNodes. The construction of the inLinks and outLinks is as follows:
First, add the corresponding entries to the node class:
{}
class Node {
private:
...
typedef vector<Link*> VLinks;
Vlinks outLinks_;
Vlinks inLinks_;
public:
...
void addOutLink(Link* Link) { outLinks_.push_back(link); }
Link* outLink(int i) { return outLinks_[i]; }
int nOutLinks() { return outLinks_.size(); }
void addInLink(Link* link) { inLinks_.push_back(link); }
Link* inLink(int i) { return inLinks_[i]; }
int nInLinks() { return inLinks_.size() ; }
} ;
Note that we do not need the associative array property here for outLinks_ or inLinks_, and so we use the vector class
instead of map.
Next, we generate the information of which links are incoming and outgoing. The easiest way is to add this in the readLinks routine at the end, as was already done in the previous section.