How to print Edges of Delaunay Graph? - c++

Question

Following this: How to print the faces of a Voronoi diagram?, I now have:
#include <iostream>
#include <fstream>
#include <cassert>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Segment_Delaunay_graph_2.h>
#include <CGAL/Segment_Delaunay_graph_adaptation_policies_2.h>
#include <CGAL/Segment_Delaunay_graph_traits_2.h>
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Segment_Delaunay_graph_traits_2<K> Gt;
typedef CGAL::Segment_Delaunay_graph_2<Gt> DT;
int main() {
std::ifstream ifs("data.cin");
assert( ifs );
DT vd;
DT::Site_2 site;
// read the sites from the stream and insert them in the diagram
while ( ifs >> site ) { vd.insert( site ); }
ifs.close();
// validate the diagram
assert( vd.is_valid(true, 1) );
std::cout << std::endl << std::endl;
// Iterate over edges
DT::Finite_edges_iterator eit = vd.finite_edges_begin();
for (int k = 1; eit != vd.finite_edges_end(); ++eit, ++k) {
DT::Edge e = *eit;
//std::cout << e << std::endl;
}
}
However, an edge cannot be printed that simply (with cout). How to do it?
Here is the error from another attempt:
/home/gsamaras/CGAL-4.7/code/DelaunayTOvoronoi/delTovor.cpp:30:27: error: ‘CGAL::Triangulation_ds_edge_iterator_2<CGAL::Triangulation_data_structure_2<CGAL::Segment_Delaunay_graph_vertex_base_2<CGAL::Segment_Delaunay_graph_storage_traits_2<CGAL::Segment_Delaunay_graph_traits_2<CGAL::Epick> >, CGAL::Triangulation_ds_vertex_base_2<void> >, CGAL::Segment_Delaunay_graph_face_base_2<CGAL::Segment_Delaunay_graph_traits_2<CGAL::Epick>, CGAL::Triangulation_ds_face_base_2<void> > >, true>::Edge’ has no member named ‘site’
std::cout << eit->site() << std::endl;
^

Answer 1

You can print the sites forming the edge like this:
for (int k = 1; eit != vd.finite_edges_end(); ++eit, ++k) {
DT::Edge e = *eit;
std::cout << "k = " << k << std::endl;
if ( vd.is_infinite(e.first->vertex( vd.ccw(e.second) )) )
std::cout << "infinite\n";
else
std::cout << e.first->vertex( vd.ccw(e.second) )->site() << std::endl;
if ( vd.is_infinite(e.first->vertex( vd.cw(e.second) )) )
std::cout << "infinite\n";
else
std::cout << e.first->vertex( vd.cw(e.second) )->site() << std::endl;
if ( vd.is_infinite(e.first->vertex( e.second )) )
std::cout << "infinite\n";
else
std::cout << e.first->vertex( e.second )->site() << std::endl;
if ( vd.is_infinite(vd.tds().mirror_vertex(e.first, e.second) ) )
std::cout << "infinite\n";
else
std::cout << vd.tds().mirror_vertex(e.first, e.second)->site() << std::endl;
}