摘要：这几天用mac os x 的终端g++来学c++ 编译单个文件还好，编译多个文件就出错了。undefined symbols…… 开始我还以为自己的程序出错了，花了一个下午终于知道：要Makefile 路还很长 keep moving 阅读全文

摘要：2.53(a b c)((george))((y1 y2))(y1 y2)#f#f(red shoes blue socks)2.54(define (equal? list1 list2) (cond ((or(null? list1)(null? list2))... 阅读全文

摘要：in drscheme '()=nil2.17(define (last-pair l) (if(equal? (cdr l) '()) (car l) (last-pair (cdr l))))2.18(define (reverse l) (d... 阅读全文

摘要：2.1(define (make-rat n d) (let ((abs-n (abs n)) (abs-d (abs d)) (g (gcd (abs n) (abs d)))) (if (positive? (* n d)) ... 阅读全文