問題2.19 (define us-coins (list 50 25 10 5 1)) (define uk-coins (list 100 50 20 10 5 2 1 0.5)) (define (cc amount coin-values) (cond ((= amount 0) 1) ((or (< amount 0) (no-more? coin-values)) 0) (els…続きを読む

問題2.17 (define (last-pair items) (if (null? (cdr items)) (car items) (last-pair (cdr items)))) (last-pair (list 5 2 6 10 4 8)) gosh> 8 問題2.18 (define (reverse items) (define (reverse-iter i r) (if …続きを読む

並びの表現 gauche では nil は () で表現する。 (define list1 (cons 1 (cons 2 (cons 3 (cons 4 ()))))) list1 gosh> (1 2 3 4) (define list2 (list 1 2 3 4)) list2 gosh> (1 2 3 4) (car list1) gosh> 1 (cdr list1)…続きを読む

問題2.13 パス 問題2.14 確かに計算結果が異なっている。 (define (par1 r1 r2) (div-interval (mul-interval r1 r2) (add-interval r1 r2))) (define (par2 r1 r2) (let ((one (make-interval 1 1))) (div-interval one (add-interval (d…続きを読む

問題2.12 中央値とパーセント相対許容誤差で表す数を扱うプログラム (define (make-center-percent c p) (let ((w (* c (/ p 100)))) (make-interval (- c w) (+ c w)))) (define (center i) (/ (+ (lower-bound i) (upper-bound i)) 2.0)) (defin…続きを読む

問題2.10 最初に思いついた解答 (define (div-interval x y) (if (and (< (lower-bound y) 0) (> (upper-bound y) 0)) (error "error") (mul-interval x (make-interval (/ 1.0 (upper-bound y)) (/ 1.0 (lower-…続きを読む

問題2.7 2つの区間の演算 (define (add-interval x y) (make-interval (+ (lower-bound x) (lower-bound y)) (+ (upper-bound x) (upper-bound y)))) (define (mul-interval x y) (let ((p1 (* (lower-bound x) (lower-bound …続きを読む

問題2.6 各数の定義は引数として与えられた手続き f をn回作用させる手続きを返す。 (define zero (lambda (f) (lambda (x) x))) (define one (lambda (f) (lambda (x) (f x)))) (define two (lambda (f) (lambda (x) (f (f x))))) (define three (lambd…続きを読む