CODEWITHSUNDEEP
functional-programmingschemeracket
pingchu
pingchu

Reputation: 1

How to achieve the below in scheme language?

I am trying to get the below output in scheme language. Could anybody let me know where am I wrong? I want to add .z at the end, not getting it. How can I?

code:

(define (countup n)

 (define (help i)

  (if (<= i n)

   (cons 's (help (+ i 1)))

  '()))

 (help 1 ) )

Input:

(countup 4)

desired output:

'(s s s s .z)

but coming output

'(s s s s)

Upvotes: 0

Views: 74

Answers (1)

stchang
stchang

Reputation: 2540

As @molbdnilo mentioned, it has to with output style of proper (ie, null-terminated) vs improper lists.

#lang racket
(cons 's (cons 's (cons 's (cons 's 'z))))            ; => '(s s s s . z)
(cons 's (cons 's (cons 's (cons 's '()))))           ; => '(s s s s)
(cons 's (cons 's (cons 's (cons 's (cons 'z '()))))) ; => '(s s s s z)

Upvotes: 1

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