;; CSE 413 21sp
;; Lecture 2 demo interactions part 1


Welcome to DrRacket, version 8.0 [cs].
Language: racket, with debugging; memory limit: 128 MB.
> 42
42
> (+ 3 4 5)
12
> +
#<procedure:+>
> 3
3
> (define xvii 17)
> xvii
17
> x
. . x: undefined;
 cannot reference an identifier before its definition
> (define (twice n) (* 2 n))
> twice
#<procedure:twice>
> (twice 3)
6
> (- (twice 21) 3)
39
> (define (fact n)
    (if (< n 2)
        1
        (* n (fact (- n 1)))))
> fact
#<procedure:fact>
> (fact 0)
1
> (fact 1)
1
> (fact 2)
2
> (fact 5)
120
> (fact 10)
3628800
> xvii
17
> (fact xvii)
355687428096000
> (define answer 42)
> answer
42
> (fact answer)
1405006117752879898543142606244511569936384000000000
> (fact 100)
93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000
> (define double (lambda (n) (+ n n)))
> double
#<procedure:double>
> (double 17)
34
> (lambda (x y) (+ x y))
#<procedure>
> ((lambda (x y) (+ x y)) 3 xvii)
20
>