SICP_3.1-3.22

;;;;;;;;;;;3.1

(define (make-accumulator base)
  (lambda (num)
    (set! base (+ base num))
    base))

(define A (make-accumulator 5))

(A 10)
(A 10)

;;;;;;;;;;3.2

(define (make-monitored f)
  (let ((count 0))
    (define (mf x)
      (cond ((eq? x 'how-many-calls?) count)
            ((eq? x 'reset-count) (set! count 0))
            (else (begin (set! count (+ count 1))
                    (f x)))))
    mf))

(define square (lambda (x) (* x x)))
(define s (make-monitored square))

(s 100)
(s 4)
(s 'how-many-calls?)
(s 'reset-count)
(s 'how-many-calls?)

先跳过了一些，等3.2后再看

开始用完全用Scheme来写

开始用Linux系统