SICP 問題1.32
;; 再帰的プロセスで (define (accumulate combiner null-value term a next b) (if (> a b) null-value (combiner (term a) (accumulate combiner null-value term (next a) next b)))) ;; 反復的プロセスで (define (accumulate combiner null-value term a next b) (define (iter a result) (if (> a b) result (iter (next a) (combiner (term a) result)))) (iter a null-value))