CGAL: get the info of nearest neighbors

Question

I am using the Point_set_2 data structure in order to find k nearest neighbors of a query point, I want to retrieve the index of neighbors; I used the following code, but it->info() produces errors! I have also seen this post, but for me the priority is using Point_set_2 method:

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Delaunay_triangulation_2.h>
#include <CGAL/Triangulation_vertex_base_with_info_2.h>
#include <CGAL/Point_set_2.h>
#include <vector>

typedef CGAL::Exact_predicates_inexact_constructions_kernel       K;
typedef CGAL::Triangulation_vertex_base_with_info_2<unsigned, K>  Vb;
typedef CGAL::Triangulation_data_structure_2<Vb>                  Tds;
typedef CGAL::Delaunay_triangulation_2<K, Tds>                    Delaunay;
//typedef Delaunay::Point                                             Point;
typedef CGAL::Point_set_2<K,Tds>::Edge_iterator                   Edge_iterator;
typedef CGAL::Point_set_2<K,Tds>::Vertex_handle                   Vertex_handle;
typedef K::Point_2                                                Point_2;

CGAL::Point_set_2<K,Tds> PSet;

int main()
{
  std::vector< std::pair<Point_2,unsigned> > points;
  points.push_back( std::make_pair(Point_2(0,0),0)   );
  points.push_back( std::make_pair(Point_2(1,0),1)   );
  points.push_back( std::make_pair(Point_2(0,1),2)   );
  points.push_back( std::make_pair(Point_2(14,4),3)  );
  points.push_back( std::make_pair(Point_2(2,2),4)   );
  points.push_back( std::make_pair(Point_2(-4,0),5)  );

  PSet.insert(points.begin(),points.end());
   // init
  Point_2 actual(30,45,10);
  // nearest neighbor ...
  Vertex_handle v = PSet.nearest_neighbor(actual);
  std::cout << "Nearest neighbor:" << v->point() << "\n";
  // k nearest neighbors ...
  std::vector<Vertex_handle> L;
  std::vector<Vertex_handle>::const_iterator it;
  PSet.nearest_neighbors(actual,5, std::back_inserter(L));
  std::cout << "actual point: " << actual << "\n";
  for (it=L.begin();it != L.end(); it++)
      std::cout << it->info() << "\n";
  return 0;
}

Answer 1

A Vertex_handle is roughly equivalent of a pointer. To access it data member you have to either dereference it or use the -> operator. If you have a vector of Vertex_handle, then iterator are over Vertex_handle which means that you have to dereference the iterator to access the Vertex_handle. You should write (*it)->info().

Maybe the confusion came from the fact that the iterators of the triangulation are implicitly convertible to the handle types.