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[Alessandro Attanasi <>]

Hi,

I'm not understanding the behaviour of the graham_andrew_scan()

what should I expect if I have the following points?

               q7

                          q4

q1     q2      q3

                          q5

               q6

 q1  (-1,0) 

 q2  (0,0) 

 q3  (1,0) 

 q4  (2,1) 

 q5  (2,-1) 

 q6  (1.5,-2) 

 q7  (1.5,2) 

I filled a std::vector<Point_2> scan_test with this points in the order given by the numbers above, then I called

CGAL::graham_andrew_scan(scan_test.begin(),scan_test.end(),std::back_inserter(scan_result));

being std::vector<Point_2> scan_result.

And as result I obtained 

q1,q3,q4 into scan_result. Why?

Thanks 

Alessandro