Petar Kapriš
1b2b2dfec1
To be noted: the last two exercises, 2.15 and 2.16 were left unfinished, and will be left for another time.
25 lines
626 B
Scheme
25 lines
626 B
Scheme
#lang sicp
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(define (make-interval a b) (cons a b))
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(define (lower-bound i)
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(car i))
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(define (upper-bound i)
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(cdr i))
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(define (mul-interval x y)
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(let ((p1 (* (lower-bound x) (lower-bound y)))
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(p2 (* (lower-bound x) (upper-bound y)))
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(p3 (* (upper-bound x) (lower-bound y)))
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(p4 (* (upper-bound x) (upper-bound y))))
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(make-interval (min p1 p2 p3 p4)
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(max p1 p2 p3 p4))))
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(define (div-interval x y)
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(if (<= (* (lower-bound y) (upper-bound y)) 0)
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(error "division by zero")
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(mul-interval
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x
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(make-interval (/ 1.0 (upper-bound y))
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(/ 1.0 (lower-bound y))))))
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