Question

I’ve been working on the sicp and am trying to write the ‘last’ function using accumulate

(define (accumulate f x xs)
  (if (null? xs)
      x
      (f (car xs)
         (accumulate f x (cdr xs)))))

 (last '(1 2 3 4 5)) ;;=> (5)

---

I tried this but it does not work

 (define (last seq)
   (accumulate (lambda (x y) x)
               '()
               seq))

Answer 1

Try this:

(define (last lst)
  (accumulate (lambda (x y)
                (if (null? y)
                    (cons x y)
                    y))
              '() lst))