sicp 1.12

递归过程求解Pascal三角形：

 

(define (pascal-tri row col) (cond ((or (< row col) (<= row 0) (<= col 0)) 0) ((or (= col 1) (= col row)) 1) (else (+ (pascal-tri (- row 1) col) (pascal-tri (- row 1) (- col 1))))))   相关资源：敏捷开发V1.0.pptx