Scheme: simple recursion

Question

My recursive function multiplies the given area by 1.5 until it reaches 100,000. The output is supposed to be how many times it had to multiply by 1.5. I think I understand most of what I need to do, but I'm not sure what to put in my (if) statement.

(define area-multiplier
  (lambda (area)
    (if (< 100000 area)
        0         ;what do I put here?
        (+ 1 (area-multiplier (* area 1.5))))))

John Clements · Accepted Answer · 2012-09-18 16:45:13Z

1

Think about this using an example. In this case, the relevant examples are

(area-multiplier 100000)

and

(area-multiplier 100001)

What should these produce?

answered Sep 18, 2012 at 16:45

John Clements

17.3k3 gold badges39 silver badges53 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

jblittle Over a year ago

Oh, I understand. I want them to produce the amount of times area was multiplied by 1.5. Therefore, 0 was correct in that spot because it would add 0 to the total and stop recursion. Thanks!

C. K. Young · Accepted Answer · 2012-09-18 16:26:56Z

0

What you have is fine, except that if you want 100000 to return 0, then change the < to <=. :-)

answered Sep 18, 2012 at 16:26

C. K. Young

224k47 gold badges394 silver badges446 bronze badges

1 Comment

jblittle Over a year ago

I didn't even catch that. Thank you! It turned out I had a fundamental misunderstanding of how recursion worked!

Collectives™ on Stack Overflow

Scheme: simple recursion

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related