; ======================================================================
;
; 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 08/19/05
; modified:
; (保持内容完整不变前提下，可以任意转载)
; ======================================================================
;; SICP No.2.39
(define (reverse sequence)
(fold-right (lambda (x y) (append y (list x))) () sequence))
(define (reverse sequence)
(fold-left (lambda (x y) (cons y x)) () sequence))
;; Test-it:
;; Welcome to MzScheme version 209, Copyright (c) 2004 PLT Scheme, Inc.
;; > (reverse (list 1 2 3))
;; (3 2 1)
;; > (reverse ())
;; ()
