;; CSE 413 23sp lec02 interactions demo transcript (reconstructed)


Welcome to DrRacket, version 8.8 [cs].
Language: racket, with debugging; memory limit: 128 MB.
> 42
42
> (+ 1 2 3)
6
> +
#<procedure:+>
> (define n 42)
> n
42
> (+ x y)
. . x: undefined;
 cannot reference an identifier before its definition
> (define (twice n) (+ n n))
> (twice 2)
4
> (twice n)
84
> (twice (+ 1 (twice 2)))
10
> (define (fact n)
    (if (< n 2)
        1
        (* n (fact (- n 1)))))
> fact
#<procedure:fact>
> (fact 0)
1
> (fact 1)
1
> (fact 2)
2
> (fact 3)
6
> (fact 4)
24
> (fact 5)
120
> (fact 10)
3628800
> (fact n)
1405006117752879898543142606244511569936384000000000
> (fact 100)
93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000
> (fact 1024)
541852879605885728307692194468385473800155396353801344448287027068321061207337660373314098413621458671907918845708980753931994165770187368260454133333721939108367528012764993769768292516937891165755680659663747947314518404886677672556125188694335251213677274521963430770133713205796248433128870088436171654690237518390452944732277808402932158722061853806162806063925435310822186848239287130261690914211362251144684713888587881629252104046295315949943900357882410243934315037444113890806181406210863953275235375885018598451582229599654558541242789130902486944298610923153307579131675745146436304024890820442907734561827369030502252796926553072967370990758747793127635104702469889667961462133026237158973227857814631807156427767644064591085076564783456324457736853810336981776080498707767046394272605341416779125697733374568037475186676265961665615884681450263337042522664141862157046825684773360944326737493676674915098953768112945831626643856479027816385730291542667725665642276826058264393884514911976419675509290208592713156362983290989441052732125187249527501314071676405516936190781821236701912295767363117054126589929916482008515781751955466910902838729232224509906388638147771255227782631322385756948819393658889908993670874516860653098411020299853816281564334981847105777839534742531499622103488807584513705769839763993103929665046046121166651345131149513657400869056334867859885025601787284982567787314407216524272262997319791568603629406624740101482697559533155736658800562921274680657285201570401940692285557800611429055755324549794008939849146812639860750085263298820224719585505344773711590656682821041417265040658600683844945104354998812886801316551551714673388323340851763819713591312372548673734783537316341517369387565212899726597964903241208727348690699802996369265070088758384854547542272771024255049902319275830918157448205196421072837204937293516175341957775422453152442280391372407717891661203061040255830055033886790052116025408740454620938384367637886658769912790922323717371343176067483352513629123362885893627132294183565884010418727869354439077085278288558308427090461075019007184933139915558212752392329879780649639075333845719173822840501869570463626600235265587502335595489311637509380219119860471335771652403999403296360245577257963673286654348957325740999710567131623272345766761937651408103999193633908286420510098577454524068106897392493138287362226257920000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> (define (twice n) (+ n n))
> (define xvii (+ 1 (twice 8)))
> xvii
17
> (define double (lambda (n) (+ n n)))
> double
#<procedure:double>
> (double 8)
16
> (lambda (x y) (+ (x y)))
#<procedure>
> (define plus (lambda (x y) (+ x y)))
> (plus 3 4)
7
> ((lambda (x y) (* x y)) 3 4)
12
> ((lambda (w x y z) (+ w x y z)) 2 3 4 5)
14
> (1 2 3 4)
. . application: not a procedure;
 expected a procedure that can be applied to arguments
  given: 1
> '(1 2 3 4)
'(1 2 3 4)
> n
42
> 'n
'n
> '(red green blue)
'(red green blue)
> (define nums '(1 2 3 4))
> nums
'(1 2 3 4)
> (cons 0 nums)
'(0 1 2 3 4)
> (cons 1 '())
'(1)
> (cons 1 (cons 2 '()))
'(1 2)
> (cons 1 2)
'(1 . 2)
> (cons 1 (cons 2 (cons 3 (cons 4 '()))))
'(1 2 3 4)
> (car nums)
1
> (cdr nums)
'(2 3 4)
> (car (cdr nums))
2
> (car (cdr (cdr nums)))
3
> (cadr nums)
2
> (caddr nums)
3
> (cadddr nums)
4
> (define (second lst) (cadr lst))
> (second nums)
2
> (cons 1 2)
'(1 . 2)
> (cons 1 (cons 2 3))
'(1 2 . 3)
> (length nums)
4
> (reverse nums)
'(4 3 2 1)
> (define (sum lst)
    (if (null? lst)
        0
        (+ (car lst) (sum (cdr lst)))))
> (sum '())
0
> (sum '(5))
5
> (sum nums)
10
> -5
-5
>