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    <div class="moz-cite-prefix">Thanks,<br>
      <br>
      That means that the distance is de square of x^2 + y^2<br>
      Then I can make this exercise. <br>
      <br>
      Thanks. Following the book when Englisch is not your mother
      language can be diffucult sometimes.<br>
      <br>
      Roelof<br>
      <br>
      <br>
      <br>
      Op 23-6-2012 16:18, Matthias Felleisen schreef:<br>
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      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>
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        <div>On Jun 22, 2012, at 2:42 PM, Roelof Wobben wrote:</div>
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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>
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              <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>
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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>
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          ____________________<br>
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