摘要: #lang racket(define (length items) (if (null? items) 0 (+ 1 (length (cdr items)))))(define (element-of-set? x set) (cond ((null? set) fals... 阅读全文
posted @ 2015-08-20 17:05 南郭子綦 阅读(829) 评论(0) 推荐(0) 编辑