On Nov 6, 2013, at 7:13 AM, Ben Duan <yfe...@gmail.com> wrote:
> Thank you, Jens. I didn't know that the inexactness of floating point numbers
> could make such a big difference.
>From HtDP/1e:
(define JANUS
(list #i31
#i2e+34
#i-1.2345678901235e+80
#i2749
#i-2939234
#i-2e+33
#i3.2e+270
#i17
#i-2.4e+270
#i4.2344294738446e+170
#i1
#i-8e+269
#i0
#i99))
;; [List-of Number] -> Number
;; add numbers from left to right
(check-expect (sumlr '(1 2 3)) 6)
(define (sumlr l)
(foldl + 0 l))
;; [List-of Number] -> Number
;; add numbers from right to left
(check-expect (sumrl '(1 2 3)) 6)
(define (sumrl l) (foldr + 0 l))
Then apply the two functions to JANUS. Enjoy -- Matthias
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