Exercise 2.21. The procedure square-list takes a list of numbers as argument and returns a list of the squares of those numbers.
(square-list (list 1 2 3 4))
(1 4 9 16)
Here are two different definitions of square-list. Complete both of them by filling in the missing expressions:
(define (square-list items)
(if (null? items)
nil
(cons <??> <??>)))
(define (square-list items)
(map <??> <??>))
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| (define nil '()) | |
| (define (square n) (* n n)) | |
| (define (square-list items) | |
| (if | |
| (null? items) | |
| nil | |
| (cons | |
| (square (car items)) | |
| (square-list (cdr items))))) | |
| (define (square-list2 items) | |
| (map square items)) | |
| (square-list (list 1 2 3 4 5)) | |
| (square-list2 (list 1 2 3 4 5)) | |