<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div>Assuming you don't literally mean 'print', here is a function that does what you want: </div><div><br></div><div><div>;; Sentence is one of: </div><div>;; -- empty </div><div>;; -- (cons String Sentence)</div><div><br></div><div>(define s1 '("This" "is" "a" "sentence."))</div><div>(define s2 '("And" "this" "is" "one," "too."))</div><div><br></div><div>;; Sentence N -> Sentence </div><div>;; add 's' to the 2nd word in s if it is longer than i letters </div><div><br></div><div>(check-expect (change s1 2) s1)</div><div>(check-expect (change s2 3) (cons "And" (cons "thiss" (rest (rest s2)))))</div><div><br></div><div>(define (change s i)</div><div> (if (> (string-length (second s)) i)</div><div> (cons (first s) (cons (string-append (second s) "s") (rest (rest s))))</div><div> s))</div><div> </div></div><div><br></div><div>If it doesn't what you want, follow the design recipe and let us know at which step you're stuck. </div><div><br></div><div><br></div><br><div><div>On Jun 23, 2012, at 2:45 PM, Roelof Wobben wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">
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<div class="moz-cite-prefix">I have another "problem" I try to solve
in my head.<br>
<br>
Suppose I want to change one word in a sentence depening if a
comparision is true or false.<br>
<br>
I could do this in pseudo code.<br>
<br>
if comparision is true then print "it's true" else print "it's
not true"<br>
<br>
It works but I type two time's "it's true".<br>
<br>
Can this be done so I have to type only one time the sentence and
depeding on true or false the word not is used. <br>
<br>
Roelof<br>
<br>
<br>
<br>
Op 23-6-2012 16:18, Matthias Felleisen schreef:<br>
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<blockquote cite="mid:47F7EB3C-3C87-4706-B031-F51925000CCC@ccs.neu.edu" type="cite">
<div><br>
</div>
<div>Origin means (0,0) or plain 0 in English. </div>
<div><br>
</div>
<br>
<div>
<div>On Jun 22, 2012, at 2:42 PM, Roelof Wobben wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
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<div bgcolor="#FFFFFF" text="#000000"> Hello, <br>
<br>
I try to make this exercise : <br>
<br>
<div class="SIntrapara"><a moz-do-not-send="true" name="(counter._mix._(exercise._mix4))"></a><span style="font-weight: bold;">Exercise</span> 76: A
programmer has chosen to represent locations as Cartesian
points or just points:</div>
<div class="SIntrapara">
<blockquote class="SCodeFlow">
<table class="RktBlk" cellspacing="0">
<tbody>
<tr>
<td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">Location
is one of:</span></td>
</tr>
<tr>
<td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">–</span><span class="RktCmt"> Posn</span></td>
</tr>
<tr>
<td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">–</span><span class="RktCmt"> Number</span></td>
</tr>
<tr>
<td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">interp.
Posn are positions on the Cartesian grid,</span></td>
</tr>
<tr>
<td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">Numbers
are positions on the number line </span></td>
</tr>
</tbody>
</table>
</blockquote>
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<div class="SIntrapara">Design the function <span class="RktSym">in-reach</span>, which determines whether
or not a given location’s distance to the origin is
strictly less than some constant<span class="RktSym">R</span>.<br>
<br>
So I must design a function called in-reach.<br>
<br>
Am I right I need to use two structs (Posn) . One for the
given location and one for the origon ?<br>
<br>
Regards, <br>
<br>
Roelof<br>
<br>
<br>
</div>
<br>
</div>
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</blockquote>
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<br>
</blockquote>
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