38 lines
1.1 KiB
Racket
38 lines
1.1 KiB
Racket
#lang racket/base
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(define (square x) (* x x))
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(define (lengths_eq x1 y1 x2 y2 x3 y3)
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(if (equal? (+ (square(- x1 x2)) (square(- y1 y2))) (+ (square(- x3 x1)) (square(- y3 y1))))
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#t #f
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))
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(define (collinear x1 y1 x2 y2 x3 y3)
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(if (equal? (* (- x1 x2) (- y2 y3)) (* (- y1 y2) (- x2 x3)))
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#t #f
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))
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(define (perpendicular x1 y1 x2 y2 x3 y3 x4 y4)
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(if (equal? (+ (* (- x1 x2) (- x3 x4)) (* (- y1 y2) (- y3 y4))) 0 )
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#t #f
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))
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(define (simson o_x o_y a_x a_y b_x b_y c_x c_y d_x d_y e_x e_y f_x f_y g_x g_y)
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(if (and
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(lengths_eq o_x o_y a_x a_y b_x b_y)
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(lengths_eq o_x o_y a_x a_y c_x c_y)
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(lengths_eq o_x o_y a_x a_y d_x d_y)
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(collinear e_x e_y b_x b_y c_x c_y)
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(collinear f_x f_y a_x a_y c_x c_y)
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(collinear g_x g_y a_x a_y b_x b_y)
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(perpendicular b_x b_y c_x c_y d_x d_y e_x e_y)
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(perpendicular a_x a_y c_x c_y d_x d_y f_x f_y)
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(perpendicular a_x a_y b_x b_y d_x d_y g_x g_y))
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(begin (displayln "3 Points lie on one line.") (collinear e_x e_y f_x f_y g_x g_y)
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) (displayln "3 Points do not lie on one line.")
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))
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(simson 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ) |