trimmed lines not vertical

I found this problem after writing some code that relys on checking the endpoints of a line to determine if they are vertical or horizontal. If both x-components of the points are equal, its vertical. It works fine unless the line has been trimmed (or extended). Basically this is really annoying and I am wondering if anyone else has run into this and if there is a way to work around it. This is in 2005 by the way.... and trim worked fine when I tested it in R14 but extend had the same problem. Here is the code I used to test this....

(setq pt1 (getpoint "Pick First Point: "))
(setq pt2 (getpoint "Pick Second Point: "))

(if (= (car pt2) (car pt1)) "VERTICAL" "NOT VERTICAL")

P.S. Same problem when checking horizontal lines

 

when trim computes a new endpoint, the result is accurate to 8 decimal
places you are comparing the two numbers at 16 decimal places, use (equal x1
x2 0.00000001)

endpoints of a line to determine if they are vertical or horizontal. If
both x-components of the points are equal, its vertical. It works fine
unless the line has been trimmed (or extended). Basically this is really
annoying and I am wondering if anyone else has run into this and if there is
a way to work around it. This is in 2005 by the way.... and trim worked
fine when I tested it in R14 but extend had the same problem. Here is the
code I used to test this....

 

You may want to use the fuzz option of the (equal) function:

(Defun c:cp ()
(setq pt1 (getpoint "Pick First Point: "))
(setq pt2 (getpoint "Pick Second Point: "))
(if (equal (print (car pt2)) (print (car pt1)) 0.0001) "VERTICAL" "NOT VERTICAL")
)

 

Ahhhhh, thank you very much you guys. Figures it was something to do with precision.