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Lab 1 - pigl.scm
(define (pigl wd)
(if (pl-done? wd)
(word wd 'ay)
(pigl (word (bf wd) (first wd)))))
(define (pl-done? wd)
(vowel? (first wd)))
(define (vowel? letter)
(member? letter '(a e i o u)))
(transcript-on "lab1a") ; This starts a transcript file
with the name lab1a.
(load "pigl.scm") ; This reads in the file you created earlier.
(pigl ’scheme) ; Try out your program.
; Feel free to try more test cases here!
(trace pigl) ; This is a debugging aid. Watch what happens
(pigl ’scheme) ; when you run a traced procedure.
(transcript-off)
(exit)
lab1a trace
okay
STk> (load "pigl.scm")
okay
STk> (pigl 'scheme)
emeschay
STk> (trace pigl)
okay
STk> (pigl 'scheme)
.. -> pigl with wd = scheme
.... -> pigl with wd = chemes
...... -> pigl with wd = hemesc
........ -> pigl with wd = emesch
........ <- pigl returns emeschay
...... <- pigl returns emeschay
.... <- pigl returns emeschay
.. <- pigl returns emeschay
emeschay
STk>
Lab1 - plural.scm
(define (plural wd)
(if (equal? (last wd) 'y)
(word (bl wd) 'ies)
(word wd 's)))
Square Root in Scheme [SICP
1.1.7]
(define (sqrt x)
(sqrt-iter 1.0 x))
(define (sqrt-iter guess x)
(if (good-enough? guess x)
guess
(sqrt-iter (improve guess x) x)))
(define (good-enough? guess x)
(< (abs (- (square guess) x)) 0.001))
(define (improve guess x)
(average guess (/ x guess)))
Newton's Successive Approximations for finding the root of a
number
| Guess |
Quotient |
Average |
| |
| 1 |
(2/1) = 2 |
((2 + 1)/2) = 1.5 |
| |
| 1.5 |
(2/1.5) = 1.3333 |
((1.3333 + 1.5)/2) = 1.4167 |
| |
| 1.4167 |
(2/1.4167) = 1.4118 |
((1.4167 + 1.4118)/2) = 1.4142 |
| |
| 1.4142 |
... |
... |
;Lab 1 Last Letter ies
(define (plural wd)
(if (equal? (last wd) 'y)
(if (vowel? (last (bl wd)))
(word wd 's)
(word (bl wd) 'ies))
(word wd 's)))
;Lab 1 answer=a^2 + b^2 where a, b are
the bigger of a, b, c
(define (sum-square-large a b c)
(define (square x) (* x x))
(define (sumsq x y) (+ (square x) (square y)))
(if (>= a b)
(if (>= b c)
(sumsq a b)
(sumsq a c))
(if (>= a c)
(sumsq a b)
(sumsq b c))))
;Lab 1 Remove Duplicated words
(define (dupls-removed sent)
(cond ((empty? sent) '())
((member? (first sent) (bf sent))
(dupls-removed (bf sent)))
(else (sentence (first sent) (dupls-removed (bf sent))))))
> (dupls-removed ’(a b c a e d e b))
(c a d e b)
> (dupls-removed ’(a b c))
(a b c)
> (dupls-removed ’(a a a a b a a))
(b a)
3
Lab 2A Question #5
(define (type-check proc pred wd)
(if ( pred wd
)
(proc wd)
#f ;false
);if
);define
Lab2A #6
####################
(define (make-safe proc pred?)
lambda (wd)
((if ( pred? wd
)
(proc wd)
#f ;false
);if
);lambda
) ;define
SICP =
Structure and Interpretation of Computer Programs. Second Edition. Harnold
Abelson, Gerald Jay Sussman, and Julie Susman. ISBN 0262011530.
657 pages. The MIT Press. July 1996. Full Text Online
http://mitpress.mit.edu/sicp/full-text/book/book.html
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