CODEWITHSUNDEEP
algorithmfunctionrecursionracket
Tobias Heitkamp
Tobias Heitkamp

Reputation: 29

I get stuck in my recursion

I have a problem with my Racket programm. I want to add this function to my programm but I get stuck in my recursion:

Here the function:

ggt: N x N -> N
(m,n) -> 

ggT(m-n,n) if m > n

ggT(m,n-m) if n > m

m if m=n



(define (ggT m n)
  (cond
    [(> m n)(ggT (- m n)] ;; If m > n the programm should go recursiv back and change
                          ;; the value of m to m-n. But I know that this wont work this way
    [(< m n)(ggT (- n m)] ;; Same Problem here
    [else m]))

How do I start a real recursion?

Upvotes: 1

Views: 95

Answers (2)

Sean
Sean

Reputation: 62472

Your function ggT takes two parameters, but you are only passing 1 in. I think you want something like this:

(define (ggT m n)
  (cond
    [(> m n)(ggT (- m n) n)]                          
    [(< m n)(ggT m (- n m))]
    [else m]))

Upvotes: 2

&#211;scar L&#243;pez
&#211;scar L&#243;pez

Reputation: 236004

Try this:

(define (ggT m n)
  (cond [(> m n) (ggT (- m n) n)]
        [(< m n) (ggT m (- n m))]
        [else m]))

You just have to pass the parameters in the correct order when calling the ggT function, remember that ggT receives two parameters, but you were passing only one.

Upvotes: 3

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