; ======================================================================
;
; Structure and Interpretation of Computer Programs
; (trial answer to excercises)
;
; 计算机程序的构造和解释(习题试解)
;
; created: code17 03/06/05
; modified:
; (保持内容完整不变前提下，可以任意转载)
; ======================================================================
;; SICP No.1.43
(define (repeated f n)
(if (= n 1) f (compose f (repeated f (- n 1)))))
;; 或者
(define (repeated f n)
(if (= n 1) f (lambda (x) ((repeated f (- n 1)) (f x)))))
;; 或
(define (repeated f n)
(define (iter i result)
(if (= i n) result (iter (+ i 1) (lambda (x) (result (f x))))))
(iter 1 f))
;; Test-it:
;; Welcome to MzScheme version 209, Copyright (c) 2004 PLT Scheme, Inc.
;; > ((repeated square 3) 5)
;; 625
;; > ((repeated square 3) 5)
;; 390625
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