(define (sum-rec term a next b)
    (if (> a b)
        0
        (+ (term a)
           (sum-rec term (next a) next b))))

  (define (sum term a next b)
    (define (iter a result)
      (if (> a b)
          result
          (iter (next a) (+ result (term a)))))
    (iter a 0))

(define (cube n) (* n n n))
(define (inc n) (+ n 1))
(define (sum-cubes a b)
  (sum cube a inc b))
(define (sum-cubes-rec a b)
  (sum-rec cube a inc b))

(display (sum-cubes-rec 1 10))
(display "\n")
(display (sum-cubes 1 10))
(display "\n")