29 lines
723 B
Racket
29 lines
723 B
Racket
#lang racket
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(define (% a b) (- a (* b (truncate (/ a b)))))
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(define (bearing- bearing heading)
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(- (% (+ (% (- bearing heading) 360) 540) 360) 180))
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(module+ main
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(bearing- 20 45)
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(bearing- -45 45)
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(bearing- -85 90)
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(bearing- -95 90)
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(bearing- -45 125)
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(bearing- -45 145)
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(bearing- 29.4803 -88.6381)
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(bearing- -78.3251 -159.036)
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(bearing- -70099.74233810938 29840.67437876723)
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(bearing- -165313.6666297357 33693.9894517456)
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(bearing- 1174.8380510598456 -154146.66490124757)
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(bearing- 60175.77306795546 42213.07192354373))
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(module+ test
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(require rackunit)
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(check-equal? (% 7.5 10) 7.5)
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(check-equal? (% 17.5 10) 7.5)
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(check-equal? (% -7.5 10) -7.5)
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(check-equal? (% -17.5 10) -7.5))
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