;;; 2.9.scm
;;; created on 2014-02-12
;;; $Id: 2.9.scm 1.2 2024/12/07 09:09:04 s Exp $
(define (main args)
  ; input
  (define r 0.05)
  (define pv 20e3)
  (define n1 20)
  (define n2  5)
  (define i1 (iota n1 1) )
  (define i2 (iota n2 1) )

  ; calculation
  (define sumdf1 (fold + 0 (map (lambda (x) (/ 1 (expt (+ 1 r) x))) i1)))
  (define sumdf2 (fold + 0 (map (lambda (x) (/ 1 (expt (+ 1 r) x))) i2)))
  (define x (/ pv sumdf1))
  (define v (* x  sumdf2))

  ; output
  (print "2.9.scm")
  (print "r= "   r)
  (print "pv($)= " pv)
  (print "n1= " n1)
  (print "n2= " n2)
  (print "total of discount factors= "    sumdf1)
  (print "each year's cost($)= "          x)
  (print "present value of the roof($)= " v)
0)
;;; end