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<DIV dir=ltr align=left><SPAN class=029482418-22032013><FONT color=#0000ff
size=2 face="Courier New">I'll be happy to help. I assume you are dealing with
an exercise. Is this a self-study or do you have a teacher? If you have a
teacher he or she is the best person to help you. Can you show me what you have
so far? (if you like off list) Without some more input from your part, it
is difficult to provide clues how to proceed without revealing too much. Which
language are you using? May be one of the student languages of Racket?
</FONT></SPAN><SPAN class=029482418-22032013><FONT color=#0000ff size=2
face="Courier New"></FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=029482418-22032013><FONT color=#0000ff
size=2 face="Courier New">Best wishes, Jos</FONT></SPAN></DIV><BR>
<BLOCKQUOTE
style="BORDER-LEFT: #0000ff 2px solid; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left>
<HR tabIndex=-1>
<FONT size=2 face=Tahoma><B>From:</B> users-bounces@racket-lang.org
[mailto:users-bounces@racket-lang.org] <B>On Behalf Of </B>Andrew
Regnery<BR><B>Sent:</B> jueves, 21 de marzo de 2013 20:51<BR><B>To:</B>
users@racket-lang.org<BR><B>Subject:</B> [racket] Graphing
Help<BR></FONT><BR></DIV>
<DIV></DIV>
<P
style="BACKGROUND-COLOR: rgb(255,255,255); MARGIN: 1em 0px; FONT-FAMILY: serif; FONT-SIZE: medium">Hi
All,</P>
<P
style="BACKGROUND-COLOR: rgb(255,255,255); MARGIN: 1em 0px; FONT-FAMILY: serif; FONT-SIZE: medium">I
am currently struggling with this function below. Can anyone help me
out? </P>
<P
style="BACKGROUND-COLOR: rgb(255,255,255); MARGIN: 1em 0px; FONT-FAMILY: serif; FONT-SIZE: medium"><BR></P>
<P
style="BACKGROUND-COLOR: rgb(255,255,255); MARGIN: 1em 0px; FONT-FAMILY: serif; FONT-SIZE: medium">Write
the following two functions.</P>
<P
style="BACKGROUND-COLOR: rgb(255,255,255); MARGIN: 1em 0px; FONT-FAMILY: serif; FONT-SIZE: medium">
<TABLE class=RktBlk cellSpacing=0>
<TBODY>
<TR>
<TD
style="PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: baseline"><SPAN
style="FONT-FAMILY: monospace" class=hspace> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>;</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)" class=RktCmt>a
graph is</SPAN></TD></TR>
<TR>
<TD
style="PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: baseline"><SPAN
class=RktPlain><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN></SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>;</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>(make-graph (listof symbol) (symbol -> (listof
symbol)))</SPAN></TD></TR>
<TR>
<TD
style="PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: baseline"><SPAN
class=RktPlain><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN></SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(132,60,36)"
class=RktPn>(</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(38,38,128)" class=RktSym><A
style="COLOR: black; FONT-WEIGHT: bold; TEXT-DECORATION: none"
class=RktStxLink
href="http://docs.plt-scheme.org/htdp-langs/intermediate-lambda-unchanged.html#(form._((lib._lang%2Fhtdp-intermediate-lambda..rkt)._define-struct))">define-struct</A></SPAN><SPAN
style="FONT-FAMILY: monospace" class=hspace> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(38,38,128)"
class=RktSym>graph</SPAN><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(132,60,36)"
class=RktPn>(</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(38,38,128)"
class=RktSym>nodes</SPAN><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(38,38,128)"
class=RktSym>neighbor</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(132,60,36)"
class=RktPn>)</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(132,60,36)"
class=RktPn>)</SPAN></TD></TR>
<TR>
<TD
style="PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: baseline"><SPAN
class=RktPlain><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN></SPAN></TD></TR>
<TR>
<TD
style="PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: baseline"><SPAN
class=RktPlain><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN></SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>;</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>has-self-loop? : graph -> boolean</SPAN></TD></TR>
<TR>
<TD
style="PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: baseline"><SPAN
class=RktPlain><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN></SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>;</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>Determines whether any node in the given graph is its own
neighbor</SPAN></TD></TR>
<TR>
<TD
style="PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: baseline"><SPAN
class=RktPlain><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN></SPAN></TD></TR>
<TR>
<TD
style="PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: baseline"><SPAN
class=RktPlain><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN></SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>;</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>has-cycle? : graph -> boolean</SPAN></TD></TR>
<TR>
<TD
style="PADDING-LEFT: 0px; PADDING-RIGHT: 0px; VERTICAL-ALIGN: baseline"><SPAN
class=RktPlain><SPAN style="FONT-FAMILY: monospace"
class=hspace> </SPAN></SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>;</SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt> </SPAN><SPAN
style="FONT-FAMILY: monospace; COLOR: rgb(194,116,31)"
class=RktCmt>Determines whether the given graph has a
cycle.</SPAN></TD></TR></TBODY></TABLE></P><SPAN
style="BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: serif; FONT-SIZE: medium">A </SPAN><B
style="BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: serif; FONT-SIZE: medium">cycle</B><SPAN
style="BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: serif; FONT-SIZE: medium"> is
a path from a node to itself, and a </SPAN><B
style="BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: serif; FONT-SIZE: medium">self-loop</B><SPAN
style="BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: serif; FONT-SIZE: medium"> is
a special case of a cycle that consists of only a single edge.</SPAN>
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