C++ Boost graph library: Building a vector of vertices visited in an undirected graph search?

Question

From what I can gather of how to use BGL in order to invoke a DFS of a graph from a known root node I need to do something along the lines of

class MyVisitor : public boost::default_dfs_visitor
{
  public:
  void discover_vertex(MyVertex v, const MyGraph& g) const
 {
    cerr << v << endl;
    return;
 }

};


 void bfsMethod(Graph g, int rootNodeId)
 {

   boost::undirected_dfs(g, vertex(rootNodeId,g), boost::visitor(vis)); 

 }

Now I am not sure how I alter this so that std::vector of vertexId's (or pointers) is built as the DFS visits all vertices in the graph in a similar way to how the minimum spanning tree algorithm can be used eg

std::vector < JPEdge > spanning_tree;
kruskal_minimum_spanning_tree(g, std::back_inserter(spanning_tree));

Answer 1

The vector must be a member of your visitor. In the discover_vertex function, just push the discovered element into the vector.

class MyVisitor : public boost::default_dfs_visitor
{
  public:
  void discover_vertex(MyVertex v, const MyGraph& g) const
 {
    cerr << v << endl;
    vv.push_back(v);
    return;
 }

  vector<MyVertex> GetVector() const {return vv; }

 private: 
 vector<MyVertex> vv;

};

void bfsMethod(Graph g, int rootNodeId)
{
  MyVisitor vis;
  boost::undirected_dfs(g, vertex(rootNodeId,g), vis); 
  vector<MyVertex> vctr = vis.GetVector();

 }