Thread: Point in or out

  1. #1
    Registered User
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    Apr 2010

    Point in or out


    Given a polygon (could be regular, irregular, convex, concave), find out whether a particular point lies inside it or outside it.

    This question was asked within an interview. what should be the approach to get this information.


  2. #2
    Jack of many languages Dino's Avatar
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    Nov 2007
    Katy, Texas
    For a 2D polygon, if you raytrace (draw) a line across it, depending on how many edges of the polygon your cross, the point is inside or outside the polygon.

    Another way might be its bounding box, depending on how the bounding boxes are defined for that object.
    Mac and Windows cross platform programmer. Ruby lover.

    Quote of the Day
    12/20: Mario F.:I never was, am not, and never will be, one to shut up in the face of something I think is fundamentally wrong.

    Amen brother!

  3. #3
    and the hat of int overfl Salem's Avatar
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    Aug 2001
    The edge of the known universe
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  4. #4
    Registered User claudiu's Avatar
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    Feb 2010
    London, United Kingdom
    As Salem pointed out, generally figuring out the correct place where to ask questions is a far more important thing for you to work on that finding an algorithm that solves the given problem.
    1. Get rid of gets(). Never ever ever use it again. Replace it with fgets() and use that instead.
    2. Get rid of void main and replace it with int main(void) and return 0 at the end of the function.
    3. Get rid of conio.h and other antiquated DOS crap headers.
    4. Don't cast the return value of malloc, even if you always always always make sure that stdlib.h is included.

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