title: Printing arrangements_2 in CGAL vertex-wise
body: <p>So I have a disparate number of line segments which I want to combine to form a polygon. So imagine 4 points <code>p0,p1,p2,p3</code> which form a open polygon <code>p0-p1-p2-p3</code>. (This is illustrative : the polygon could be closed also)</p>
  
  <p>But my algorithm generates the segments in random order say <code>(p2,p3) (p0,p1) (p1,p2)</code>. Hence to combine them coherently I used the <strong>Arrangements_2</strong> class in CGAL. </p>
  
  <p>I have combined them. But now they form a single polygon with an unbounded face. I am not so sure how can I print out the vertex in an orderly fashion. </p>
  
  <p>What I want is the algorithm to output (p0-p1-p2-p3) OR (p3-p2-p1-p0).</p>
  
  <p>I looked at the documentation <a href="http://www.cgal.org/Manual/3.3/doc_html/cgal_manual/Arrangement_2/Chapter_main.html#Subsection_20.2.2" rel="nofollow">link here</a> and they have a nice traversal order for bounded faces but not so much for unbounded faces. </p>
  
  <p>My questions :</p>
  
  <ol>
  <li><p>Can I achieve the same using traversals for unbounded face ?</p></li>
  <li><p>If not <strong>Arrangements_2</strong> what else can I use in CGAL to achieve the same thing ? (The next best thing I can think of is writing a DS myself) </p></li>
  </ol>