【SICP练习】136 练习3.67

练习3-67

原文

Exercise 3.67. Modify the pairs procedure so that (pairs integers integers) will produce the stream of all pairs of integers (i,j) (without the condition i < j). Hint: You will need to mix in an additional stream.

代码

(define (all-pairs s t)        (cons-stream                 (list (stream-car s) (stream-car t))                (interleave                        (interleave                                (stream-map (lambda (x) (list (stream-car s) x))                                                        (stream-cdr t))                                (all-pairs (stream-cdr s) (stream-cdr t)))                        (stream-map (lambda (x) (list x (stream-car t)))                                                (stream-cdr s)))))

---

---

感谢您的访问，希望对您有所帮助。 欢迎大家关注或收藏、评论或点赞。

---

为使本文得到斧正和提问，转载请注明出处：
http://blog.csdn.net/nomasp

---