class vessel
{
public:
    double Vol,Temp;
    void set_para(double nVol, double nTemp);
};
void vessel::set_para(double nVol, double nTemp)
{
    Vol=nVol;
    Temp=nTemp;
}

int main()
{
    ListDigraph g;
    ListDigraph::Node u = g.addNode();
    ListDigraph::Node v = g.addNode();
    ListDigraph::Arc a = g.addArc(u, v);

    ListDigraph::NodeMap<string> name(g);
    ListDigraph::NodeMap<vessel> vessel_property(g);

    name[u] = "Tank";
    name[v] = "Filter";

    vessel_property[u].set_para(0.5, 300);
    vessel_property[v].set_para(0.6, 200);

    cout<<"The temperature of vessel "<<name[u]<<" is "<<vessel_property[u].Temp<<endl;

    return 0;
}

digraphWriter(g, "out.lgf")
    .nodeMap("Name", name)
    .run();