cgal-code

#include 
#include 
#include 

typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef K::Point_2 Point_2;

int main()
{
  Point_2 points[5] = { Point_2(0,0), Point_2(10,0), Point_2(10,10), Point_2(6,5), Point_2(4,1) };
  Point_2 result[5];

  Point_2 *ptr = CGAL::convex_hull_2( points, points+5, result );
  std::cout <<  ptr - result << " points on the convex hull" << std::endl;
  return 0;
}

#include 
#include 

#include 

typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef K::Point_2 Point_2;
typedef std::vector Points;

int main()
{
  Points points, result;
  points.push_back(Point_2(0,0));
  points.push_back(Point_2(10,0));
  points.push_back(Point_2(10,10));
  points.push_back(Point_2(6,5));
  points.push_back(Point_2(4,1));


  CGAL::convex_hull_2( points.begin(), points.end(), std::back_inserter(result) );
  std::cout << result.size() << " points on the convex hull" << std::endl;
  return 0;
}

#include 
#include 
#include 
#include 

typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef K::Point_2 Point_2;

int main()
{
  std::istream_iterator< Point_2 >  input_begin( std::cin );
  std::istream_iterator< Point_2 >  input_end;
  std::ostream_iterator< Point_2 >  output( std::cout, "n" );
  CGAL::convex_hull_2( input_begin, input_end, output );
  return 0;
}