check undefined variable scheme

[Gianmaria Lari]

The following function increase a counter by 1 and return it as string

#(define count 0) 

#(define (nextcount) (begin

                      (set! count (+ 1 count))

                      (number->string count)

                      )

   )

Is my code ok, or I should write it in a different way?

Is it possible to define "count" inside the function just in case it is undefined?

Thank you, g.