CGAL users discussion list

[Andreas Fabri <>]

Hello,

what you observe is not CGAL specific. You would also have it with

#include <iostream>
int main()
{
  double x;
  std:cin >> x;
  std::cout << x << std::endl;
  return 0;
}

You have to increase the precison.
http://www.cplusplus.com/reference/iostream/ios_base/precision/

#include <iostream>
int main()
{
  double x;
  std:cin >> x;
  std::cout.precision(20);
  std::cout << x << std::endl;
  return 0;
}

best regards,

andreas


pratihast22089 wrote:
> Sebastien Loriot wrote:
> > pratihast22089 wrote:
> > > hi,
> > >
> > > I am facing one simple problem regarding file stream. 
> > > I have the data file  like this:
> > >
> > > 257507.75  471326.93  44.51
> > >  257507.77  471326.90  44.49
> > >  257507.89  471326.93  44.04
> > >  257507.81  471326.81  44.51
> > >  257507.89  471326.87  44.10
> > >
> > >
> > > While Reading and writing file stream, it  truncate the number behind
> > > point 
> > > of first two columns but not for the third column.
> > >
> > > output:
> > >
> > >  257507  471326  44.51
> > >  257507  471326  44.49
> > >  257507  471326  44.04
> > >  257507  471326  44.51
> > >  257507  471326  44.10
> > >
> > >
> > > I had included the #include <CGAL/double.h> header file.
> > >
> > > Could you please help me in this regrads.
> > > Thank you in advance.
> > >
> > > Regards,
> > > Arun K Pratihast
> > >
> > >
> > >
> > >   
> > Hello,
> >
> > Could you please post a minimal example so that we can reproduce the 
> > problem encountered.
> >
> >
> > S.
> >
> > --
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> > https://lists-sop.inria.fr/wws/info/cgal-discuss
>
> hi,
> Here is my code:
> #include "stdafx.h"
>
> #include <cassert>
> #include <vector>
> #include <fstream>
>
> #include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
>
> #include <CGAL/Weighted_alpha_shape_euclidean_traits_3.h>
> #include <CGAL/Regular_triangulation_3.h>
> #include <CGAL/Alpha_shape_3.h>
> #include <CGAL/double.h>
>
> #include <list>
> #include <cassert>
> #include <vector>
> #include <fstream>
> #include <utility> 
>
> typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
>
> typedef CGAL::Weighted_alpha_shape_euclidean_traits_3<K> Gt;
>
> typedef CGAL::Alpha_shape_vertex_base_3<Gt>         Vb;
> typedef CGAL::Alpha_shape_cell_base_3<Gt>           Fb;
> typedef CGAL::Triangulation_data_structure_3<Vb,Fb> Tds;
> typedef CGAL::Regular_triangulation_3<Gt,Tds>       Triangulation_3;
> typedef CGAL::Alpha_shape_3<Triangulation_3>        Alpha_shape_3;
>
> typedef Alpha_shape_3::Alpha_iterator         Alpha_iterator;
> typedef Alpha_shape_3::Cell_handle          Cell_handle;
> typedef Alpha_shape_3::Vertex_handle        Vertex_handle;
> typedef Alpha_shape_3::Facet                Facet;
> typedef Alpha_shape_3::Edge                 Edge;
> typedef Gt::Weighted_point                  Weighted_point;
> typedef Gt::Bare_point                      Bare_point;
> typedef K::Point_3                          Point;
> typedef std::list<Vertex_handle>::const_iterator Vl_it;
>
>
> int main()
> {
>   std::list<Weighted_point> lwp;
>  
>     //read input
>   std::ifstream is("D:/Cgalcode/Polyhedronification/Debug/demo.xyz");
>   int n;
>   is >> n;
>   std::cout << "Point Reading Start:" << n << " points " << std::endl;
>  
>   Bare_point p;
>   for( ; n>0 ; n--)    {
>     is >> p;
>         std::cout<< p<<std::endl;
>     lwp.push_back(p);
>   }
>   std::cout << "Point Reading End:" << std::endl;
>
>                 Alpha_shape_3  as(lwp.begin(), lwp.end(), 0.5, 
> Alpha_shape_3::GENERAL);
>                 //Alpha_shape_3 as(lwp.begin(), lwp.end(), 
> Alpha_shape_3::GENERAL);;
>                 Alpha_iterator aa = as.alpha_upper_bound(1);
>                 as.set_alpha(*aa);
>
>
>   //build alpha_shape  in GENERAL mode and set alpha=0.15
>   //Alpha_shape_3  as(lwp.begin(), lwp.end(), 0.015,
> Alpha_shape_3::GENERAL);
>
>   //explore the 0.15-shape - It is dual to the boundary of the union.
>   std::list<Cell_handle> cells;
>   std::list<Facet>       facets;
>   std::list<Edge>        edges;
>   
>  
> as.get_alpha_shape_cells(std::back_inserter(cells),Alpha_shape_3::INTERIOR);
>   as.get_alpha_shape_facets(std::back_inserter(facets),
> Alpha_shape_3::REGULAR);
>   as.get_alpha_shape_facets(std::back_inserter(facets),
> Alpha_shape_3::SINGULAR);
>   as.get_alpha_shape_edges(std::back_inserter(edges), 
> Alpha_shape_3::SINGULAR);
>   std::cout << " The 0.15-shape has : " << std::endl;
>   std::cout << cells.size() << " interior tetrahedra" << std::endl;
>   std::cout << facets.size() << " boundary facets" << std::endl;
>   std::cout << edges.size()  << " singular edges" << std::endl;
>  
>
> std::list<Vertex_handle> al_vs;
> as.get_alpha_shape_vertices(back_inserter(al_vs),Alpha_shape_3::REGULAR);
> //as.get_alpha_shape_vertices(back_inserter(al_vs),Alpha_shape_3::SINGULAR);
> std::cout << al_vs.size() << " Vertex Size" << std::endl;
>
>
> //Appending my code
> std::cout << " My alpha point " << std::endl;
> std::ofstream of;
> of.open("D:/Cgalcode/Polyhedronification/data/arun/out_test1.xyz" );
>
> for(Vl_it it=al_vs.begin();it!=al_vs.end(); it++) {
>         
>         std::cout <<(*it)->point()<< std::endl;
>         of<<(*it)->point()<<"\n";
>    
> }
>
>
>   return 0;
> }