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[R Abilash <>]

I got the following code from
https://doc.cgal.org/latest/Polygon_mesh_processing/Polygon_mesh_processing_2mesh_slicer_example_8cpp-example.html

I want to know the members of the Polylines data structure.

Can some one guide me?

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/AABB_halfedge_graph_segment_primitive.h>
#include <CGAL/AABB_tree.h>
#include <CGAL/AABB_traits.h>
#include <CGAL/Polygon_mesh_slicer.h>
#include <fstream>
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Surface_mesh<K::Point_3> Mesh;
typedef std::vector<K::Point_3> Polyline_type;
typedef std::list< Polyline_type > Polylines;
typedef CGAL::AABB_halfedge_graph_segment_primitive<Mesh> HGSP;
typedef CGAL::AABB_traits<K, HGSP>    AABB_traits;
typedef CGAL::AABB_tree<AABB_traits>  AABB_tree;
int main(int argc, char* argv[])
{
  const char* filename = (argc > 1) ? argv[1] : "slider.off";
  std::ifstream input(filename);
  Mesh mesh;
  if (!input || !(input >> mesh) || mesh.is_empty()
             || !CGAL::is_triangle_mesh(mesh)) {
    std::cerr << "Not a valid input file." << std::endl;
    return 1;
  }
  // Slicer constructor from the mesh
  CGAL::Polygon_mesh_slicer<Mesh, K> slicer(mesh);
  Polylines polylines;
  slicer(K::Plane_3(0, 0, 1, -0.4), std::back_inserter(polylines));
  std::cout << "At z = 0.4, the slicer intersects "
            << polylines.size() << " polylines" << std::endl;
  polylines.clear();
  slicer(K::Plane_3(0, 0, 1, 0.2), std::back_inserter(polylines));
  std::cout << "At z = -0.2, the slicer intersects "
            << polylines.size() << " polylines" << std::endl;
  polylines.clear();
  // Use the Slicer constructor from a pre-built AABB_tree
  AABB_tree tree(edges(mesh).first, edges(mesh).second, mesh);
  CGAL::Polygon_mesh_slicer<Mesh, K> slicer_aabb(mesh, tree);
  slicer_aabb(K::Plane_3(0, 0, 1, -0.4), std::back_inserter(polylines));
  std::cout << "At z = 0.4, the slicer intersects "
            << polylines.size() << " polylines" << std::endl;
  polylines.clear();
  return 0;
}

Thank you.