#lang sicp

(define (cont-frac n d k)
  (define (cf-acc n d k i)
    (if (= k i)
        (/ (n i) (d i))
        (/ (n i) (+ (d i) (cf-acc n d k (+ i 1))))))
  (cf-acc n d k 0))

; it takes exactly k = 10, for 1/phi to be estimated accurately up to the
; 4th decimal