Just lift aux out.
> On Feb 13, 2017, at 3:18 PM, Angus Comber <[email protected]> wrote: > > If I change the code to: > > (define (maxval lst) > (define (aux lst max) > (cond [(null? lst) max] > [(> (car lst) max) (aux (cdr lst) (car lst))] > [#t (aux (cdr lst) max)])) > (aux lst 0)) > > and comment out #lang racket at the top of the file and select Beginning > Student as the language then I get error: > > define: expected only one expression for the function body, but found 1 extra > part > > Is this because there is a 2nd define in the function? Or do I need some > syntax to indicate to run aux at the end of the definition. > > On 12 February 2017 at 21:34, Matthias Felleisen <[email protected]> wrote: > > > On Feb 12, 2017, at 3:00 PM, Angus <[email protected]> wrote: > > > > I am a beginner Racket developer by the way. > > > > Here is my maxval function which is supposed to take a list and return the > > largest integer in the list. > > > > (define (maxval lst) > > (define (aux lst max) > > (cond [(null? lst) max] > > [(car lst) > max (aux (cdr lst) (car lst))] > > [#t (aux (cdr lst) max)])) > > (aux lst 0)) > > > > > > Using the function always returns the last value in the list > > > >> (maxval (list 1 2 3 5 6 1)) > > 1 > > > > The code looks correct to me, but I must be missing something. What have I > > done wrong? > > > Your code is 100% correct, conceptually. Sadly, it’s suffering from a mistake > that I saw many many times in the 90s and before. And that’s precisely why we > get beginners started on Beginning Student Language in DrRacket instead of > plain Racket. Try it out for your next few exercises or even this one, to see > whether the error message would have helped. > > — Matthias > > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
