Write connected components of a graph using Boost Graph

I have an file that is a long list of weighted edges, in the following form

node1_id node2_id weight
node1_id node3_id weight

and so on. So one weighted edge per line.

I want to load this file into boost graph and find the connected components in the graph. Each of these connected components is a subgraph. For each of these component subgraphs, I want to write a file that contains its edges in the above-described format. I want to do all this using boost graph.

This problem is in principle simple, it's just I'm not sure how to implement it neatly because I don't know my way around Boost Graph. I have already spent some hours and have code that will find the connected components, but my version is surely much longer and more complicated that necessary---I'm hoping there's a boost-graph ninja out there that can show me the right, easy way.

Because it was requested, here's the code I have so far. I don't think I'm using boost here in the most efficient or elegant way, and this solution is not complete (I don't take the subgraphs and p开发者_如何学Pythonrint out each of their edges to separate files). #include #include #include #include #include #include

using namespace std;

typedef adjacency_list <vecS,
                        vecS,
                        undirectedS,
                        property<edge_weight_t float>
                        > AdjListGraph;

void writeConnectedComponents(char *filename)
{
  AdjListGraph G;
  ifstream inputFile;
  inputFile.open(filename);  
  unsigned int id1, id2;
  float weight;
  string lineread;
  stringstream ss;
  while(getline(inputFile, lineread))
    {
      ss.clear();
      ss.str("");
      ss << lineread;
      ss >> id1;
      ss >> id2;
      ss >> weight;
      add_edge(id1, id2, weight, G);
    }
  /* Following vector contains the component number of each node */
  vector<int> components(num_vertices(G));

I used Boost.Graph to build Gnocchi.

The learning curve is quite steep. Getting the book on this library is essential I think. What helped me learn about the library is to actually modify it to make it do what I wanted. Later I found out how to use it properly. I touched only a small part of the library but the way they did things is very interesting. There are also bindings for Python, so I think it is worth it to spend some time learning it.