121 lines
3.3 KiB
HTML
121 lines
3.3 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3O//DTD W3 HTML 2.0//EN">
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<!Originally converted to HTML using LaTeX2HTML 95 (Thu Jan 19 1995) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds >
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<HEAD>
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<TITLE> Exercises</TITLE>
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</HEAD>
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<BODY>
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<meta name="description" value=" Exercises">
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<meta name="keywords" value="lp">
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<meta name="resource-type" value="document">
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<meta name="distribution" value="global">
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<P>
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<BR> <HR>
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<A HREF="node15.html"><IMG ALIGN=BOTTOM ALT="next" SRC="next_motif.gif"></A>
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<A HREF="node2.html"><IMG ALIGN=BOTTOM ALT="up" SRC="up_motif.gif"></A>
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<A HREF="node13.html"><IMG ALIGN=BOTTOM ALT="previous" SRC="previous_motif.gif"></A> <BR>
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<A HREF="lp.html"><B>Contents</B></A>
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<B> Next:</B>
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<A HREF="node15.html"> Defining Lisp functions</A>
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<B>Up:</B>
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<A HREF="node2.html"> LISt Processing</A>
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<B> Previous:</B>
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<A HREF="node13.html"> Setf</A>
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<BR> <HR> <P>
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<H1> Exercises</H1>
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<P>
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Note: A temptation if you are not used to computers is to sit down
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and try to work out these exercises in your head and be satisfied
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when you have reached some answer or other. <em> DON'T!</em> Use the Lisp
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interpreter to check your understanding. If you don't understand why
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the interpreter responds in some way, try to figure it out by playing
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with some slight variations of the problems. Some of the examples
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below (intentionally) generate interpreter errors. In such cases,
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think about why the error occurs and how you might change things to
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eliminate it.
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<P>
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<DL COMPACT><DT>1.
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<DD>Evaluate the following:
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<DL COMPACT><DT>a.
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<DD>(first '(((a)) (b c d e)))
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<DT>b.
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<DD>(rest '(((((f))))))
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<DT>c.
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<DD>(first '(rest (a b c)))
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<DT>d.
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<DD>(first '(rest (rest (a b c))))
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<DT>e.
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<DD>(cons '(my life as) '(a dog))
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<DT>f.
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<DD>(append '(my life as) '(a dog))
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<DT>g.
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<DD>(list '(my life as) '(a dog))
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<DT>h.
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<DD>(cons (rest nil) (first nil))
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<DT>i.
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<DD>(abs (- (length (rest '(((a b) (c d))))) 5))
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<DT>j.
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<DD>(reverse (cons '(rest (reverse '(its gut na mur ta give captin)))))
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<P>
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</DL>
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<P>
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<DT>2.
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<DD>Using first and rest extract the atom ``jim'' from the following:
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<DL COMPACT><DT>a.
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<DD>(he is dead jim)
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<DT>b.
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<DD>(captain (((jim) kirk)))
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<DT>c.
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<DD>(((((spock) asked) jim) if) he was all right)
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<DT>d.
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<DD>(after (looking at the (lizard man) ((((jim))) asked
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for warp 9)))
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<P>
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</DL>
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<DT>3.
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<DD> What is returned by each of the following expressions (assume
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they are evaluated in the given order)?
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<DL COMPACT><DT>a.
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<DD>(setf trek '(picard riker laforge worf))
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<DT>b.
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<DD>(cons 'data trek)
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<DT>c.
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<DD>trek
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<DT>d.
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<DD>(length (cons 'troi trek))
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<DT>e.
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<DD>(setf trek (cons 'data trek))
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<DT>f.
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<DD>(length (cons 'troi trek))
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<P>
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</DL>
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<DT>4.
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<DD>Given the following definition:
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<BLOCKQUOTE>
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<PRE>(setf mylist '((bush broccoli) (nixon watergate)
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(letterman (viewer mail))
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(you are no jack kennedy)
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(and please) (scorsese (robert deniro))))
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</PRE>
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</BLOCKQUOTE>
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Construct the following with any of the functions you have learned so
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far.
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<DL COMPACT><DT>a.
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<DD>(no broccoli please)
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<DT>b.
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<DD>((scorsese and deniro) are no robert kennedy)
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<DT>c.
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<DD>(watergate and no viewer)
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<DT>d.
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<DD>(bush nixon kennedy)
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<DT>e.
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<DD>((bush broccoli) (nixon watergate) (letterman mail))
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<P>
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</DL>
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</DL><BR> <HR>
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<P>
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<ADDRESS>
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<I>© Colin Allen & Maneesh Dhagat <BR>
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March 2007 </I>
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</ADDRESS>
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</BODY>
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