Re: point on line

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On Tue, 26 Feb 2002 01:20:39 +0000, bensler at mail.com wrote:

>
>This function will fail with 'divide by zero' errors
>
>Can I fix this easily? I'm stumped.
>
>-- check if p is on the line defined by p1 and p2
>function point_on_line(sequence p, sequence p1, sequence p2)
>   if equal(p,p1) or equal(p,p2) then return 1 end if
>   return ( (p1[2]-p[2])/(p1[1]-p[1]) ) = ( (p1[2]-p2[2])/(p1[1]-p2[1]))
>end function
>
If p1[1]-p[1] is zero it implies p & p1 is  a horizontal line,
therefore if p1[2]-p[1] is also zero the point is on the line,
otherwise not. I haven't checked this or thought about it alot though.

Pete

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