SICP 习题答案1.3

求三个数中较大的两个数之和

(define (sum-of-two x y) (+ x y) )
(define (largest-two-sum x y z)(cond( (= (min x y z) x)  (sum-of-two y z) )( (= (min x y z) y)  (sum-of-two x z) )( (= (min x y z) z)  (sum-of-two x y) ) ) )