Structure and Interpretation of Computer Programs-Exercise 1.3

標籤：sicp   lisp   

【問題】

Define a procedure that takes three numbers as arguments and returns the sum of the squares of the two larger numbers.

定義一個過程，它以三個數為參數，返回其中較大的兩個數的平方和。

【普通版】

(define (sum-square-largest x y z)  (cond ((and (> y x) (> z x)) ;; y and z are largest         (+ (* y y) (* z z)))        ((and (> x y) (> z y)) ;; x and z are largest         (+ (* x x) (* z z)))        ((and (> x z) (> y z)) ;; x and y are largest         (+ (* x x) (* y y)))))

【大神版】

(define (sum-square-largest x y z)  (cond ((and (< x y) (< x z)) ;; x is smallest         (+ (* y y) (* z z)))        (else (sum-square-largest y z x))))

Program is art