/prog/ - My first scheme program

Name: Anonymous 2012-01-17 16:31

Wrote this while bored and waiting for my functional programming class... is it... okay?



(define quad 

  (lambda (a b c)

    (define root (- (* b b) (* 4 a c)))

    (if (> root 0)

      (list 

        (/ (+ (- b) (sqrt root)) (* 2 a))

        (/ (- (- b) (sqrt root)) (* 2 a)))

      '()

    )))

Name: Anonymous 2012-01-17 16:44

It's ok, but return multiple values if possible.

Name: Anonymous 2012-01-17 16:45

Why not return complex roots, fagstrum?

Name: Anonymous 2012-01-17 16:55

>>3

(define (solve +/- b delta a)

  (/ (+/- (- b) (sqrt delta)) (* 2 a)))

(define (solve-complex +/- b delta a)

  (+/- (/ (- b) (* 2 a))

       (* +i (/ (sqrt (- delta))

                (* 2 a)))))



(define (quad a b c)

  (let ((delta (- (sqr b) (* 4 a c)))

        (solve (if (> delta 0) solve solve-complex)))

    (if (zero? delta) (- (/ b (* 2 a)))

        (values (solve + b delta a)

                (solve - b delta a)))))

Name: Anonymous 2012-01-17 17:09

>>4

$ scheme48 

Welcome to Scheme 48 1.8 (made by yellow on Sun Sep 18 01:57:41 UTC 2011)

Copyright (c) 1993-2008 by Richard Kelsey and Jonathan Rees.

Please report bugs to scheme-48-bugs@s48.org.

Get more information at http://www.s48.org/.

Type ,? (comma question-mark) for help.

(sqrt -1)

0.0+1.0i



Exit Scheme 48 (y/n)? y

$ racket

Welcome to Racket v5.1.1.

(sqrt -1)

0+1i



$

Name: Anonymous 2012-01-17 17:35

>>5
I feel retarded now.

(define (solve +/- b delta a)

  (/ (+/- (- b) (sqrt delta)) (* 2 a)))



(define (quad a b c)

  (let ((delta (- (sqr b) (* 4 a c))))

    (if (zero? delta) (- (/ b (* 2 a)))

        (values (solve + b delta a)

                (solve - b delta a)))))

Name: Anonymous 2012-01-17 22:36

moar like mah first shit program, amirite?

Name: Anonymous 2012-01-18 12:14

>>7
yeah cuz lisp is shit

My first scheme program

1 Name: Anonymous 2012-01-17 16:31

2 Name: Anonymous 2012-01-17 16:44

3 Name: Anonymous 2012-01-17 16:45

4 Name: Anonymous 2012-01-17 16:55

5 Name: Anonymous 2012-01-17 17:09

6 Name: Anonymous 2012-01-17 17:35

7 Name: Anonymous 2012-01-17 22:36

8 Name: Anonymous 2012-01-18 12:14