exam2.mht

卡耐基梅隆大学 SSD课程体系 ssd1 exam2 答案

  contents into the directory where you plan to work. The directory named <=
/span><i><span
  lang=3DEN-US style=3D'font-size:9.0pt;mso-bidi-font-size:12.0pt;font-fami=
ly:Verdana;
  mso-bidi-font-family:SimSun;color:black;mso-font-kerning:0pt'>class</span=
></i><span
  lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'> contains all compiled </span><i=
><span
  lang=3DEN-US style=3D'font-size:9.0pt;mso-bidi-font-size:12.0pt;font-fami=
ly:Verdana;
  mso-bidi-font-family:SimSun;color:black;mso-font-kerning:0pt'>.class</spa=
n></i><span
  lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'> files needed to run the simulat=
ion.
  The directory named </span><i><span lang=3DEN-US style=3D'font-size:9.0pt;
  mso-bidi-font-size:12.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>work</span></i><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'> contains all of the Java source files =
(</span><i><span
  lang=3DEN-US style=3D'font-size:9.0pt;mso-bidi-font-size:12.0pt;font-fami=
ly:Verdana;
  mso-bidi-font-family:SimSun;color:black;mso-font-kerning:0pt'>.java</span=
></i><span
  lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'>) that we are providing to you. =
The
  directory named </span><i><span lang=3DEN-US style=3D'font-size:9.0pt;mso=
-bidi-font-size:
  12.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;color:black;
  mso-font-kerning:0pt'>content</span></i><span lang=3DEN-US style=3D'font-=
size:
  9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;color:black;mso-fon=
t-kerning:
  0pt'> contains all of the HTML and image files necessary to run the simul=
ation.
  <o:p></o:p></span></p>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;text-align:left;mso-pagination:widow-orphan'><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>Load the HTML and image files to the </=
span><i><span
  lang=3DEN-US style=3D'font-size:9.0pt;mso-bidi-font-size:12.0pt;font-fami=
ly:Verdana;
  mso-bidi-font-family:SimSun;color:black;mso-font-kerning:0pt'>Content</sp=
an></i><span
  lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'> Directory of your iCarnegie Ser=
vlet
  Workbench. Then, load the </span><i><span lang=3DEN-US style=3D'font-size=
:9.0pt;
  mso-bidi-font-size:12.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>.class</span></i><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'> files into the </span><i><span lang=3D=
EN-US
  style=3D'font-size:9.0pt;mso-bidi-font-size:12.0pt;font-family:Verdana;
  mso-bidi-font-family:SimSun;color:black;mso-font-kerning:0pt'>Java_Classe=
s</span></i><span
  lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'> Directory of your iCarnegie Ser=
vlet
  Workbench. Finally, launch the </span><i><span lang=3DEN-US style=3D'font=
-size:
  9.0pt;mso-bidi-font-size:12.0pt;font-family:Verdana;mso-bidi-font-family:
  SimSun;color:black;mso-font-kerning:0pt'>initialWorldAlgaeFishCroc.html</=
span></i><span
  lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'> file using the iCarnegie Servlet
  Workbench. Please take some time and work with this servlet to understand=
 how
  it behaves. <o:p></o:p></span></p>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;text-align:left;mso-pagination:widow-orphan'><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>Create algae in a number of (say 20 to =
25)
  adjacent cells and about five catfish. Run the simulation for 10 time blo=
cks
  initially. Then, click the Refresh button of your browser repeatedly to
  single-step through each time-block. You might find some new catfish
  offspring. Note that a catfish can produce offspring only if its age is at
  least 10 time-blocks. So, a new baby will not produce offspring immediate=
ly.
  If a particular combination of initial life forms does not produce offspr=
ing,
  try a different combination.<o:p></o:p></span></p>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;text-align:left;mso-pagination:widow-orphan'><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>You may find it useful to refer to the =
<a
  href=3D"javascript:ContentByName('pg-ic-servlet-workbench-appendix');"><s=
pan
  style=3D'mso-bidi-font-size:12.0pt'>Appendix B. The iCarnegie Servlet Wor=
kbench</span></a>
  and <a href=3D"javascript:ContentByName('pg-simulation');"><span
  style=3D'mso-bidi-font-size:12.0pt'>Appendix C. Simulation of Living Bein=
gs in
  a Lake</span></a> if you need help.<o:p></o:p></span></p>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;text-align:left;mso-pagination:widow-orphan;mso-outline-level:3'><b>=
<span
  lang=3DEN-US style=3D'font-size:12.0pt;font-family:"Trebuchet MS";mso-bid=
i-font-family:
  SimSun;color:#003366;mso-font-kerning:0pt'>Files<o:p></o:p></span></b></p>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;text-align:left;mso-pagination:widow-orphan'><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>The following source file is provided. =
It
  should be downloaded to the directory where you plan to work.<o:p></o:p><=
/span></p>
  <ul type=3Ddisc>
   <li class=3DMsoNormal style=3D'color:black;mso-margin-top-alt:auto;mso-m=
argin-bottom-alt:
       auto;text-align:left;mso-pagination:widow-orphan;mso-list:l0 level1 =
lfo2;
       tab-stops:list 36.0pt'><span lang=3DEN-US style=3D'font-size:9.0pt;
       font-family:Verdana;mso-bidi-font-family:SimSun;mso-font-kerning:0pt=
'>Catfish.java
       (This file currently compiles. You have to complete the implementati=
on
       of </span><span lang=3DEN-US style=3D'font-size:12.0pt;font-family:S=
imSun;
       mso-bidi-font-family:SimSun;mso-font-kerning:0pt'>findMate</span><sp=
an
       lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-f=
ont-family:
       SimSun;mso-font-kerning:0pt'> method.) <o:p></o:p></span></li>
  </ul>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;text-align:left;mso-pagination:widow-orphan;mso-outline-level:3'><b>=
<span
  lang=3DEN-US style=3D'font-size:12.0pt;font-family:"Trebuchet MS";mso-bid=
i-font-family:
  SimSun;color:#003366;mso-font-kerning:0pt'>Tasks<o:p></o:p></span></b></p>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;text-align:left;mso-pagination:widow-orphan'><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>Complete the implementation of </span><=
span
  lang=3DEN-US style=3D'font-size:12.0pt;font-family:SimSun;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'>findMate</span><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'> method. Some hints about the </span><s=
pan
  lang=3DEN-US style=3D'font-size:12.0pt;font-family:SimSun;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'>findMate</span><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'> method are as follows:<o:p></o:p></spa=
n></p>
  <ul type=3Ddisc>
   <li class=3DMsoNormal style=3D'color:black;mso-margin-top-alt:auto;mso-m=
argin-bottom-alt:
       auto;text-align:left;mso-pagination:widow-orphan;mso-list:l2 level1 =
lfo3;
       tab-stops:list 36.0pt'><span lang=3DEN-US style=3D'font-size:9.0pt;
       font-family:Verdana;mso-bidi-font-family:SimSun;mso-font-kerning:0pt=
'>Hint
       1. Use the </span><span lang=3DEN-US style=3D'font-size:12.0pt;font-=
family:
       SimSun;mso-bidi-font-family:SimSun;mso-font-kerning:0pt'>getNeighbor=
s</span><span
       lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-f=
ont-family:
       SimSun;mso-font-kerning:0pt'> method of </span><span lang=3DEN-US
       style=3D'font-size:12.0pt;font-family:SimSun;mso-bidi-font-family:Si=
mSun;
       mso-font-kerning:0pt'>simulation</span><span lang=3DEN-US
       style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:Si=
mSun;
       mso-font-kerning:0pt'> to get the cohabitants of the catfish. <o:p><=
/o:p></span></li>
   <li class=3DMsoNormal style=3D'color:black;mso-margin-top-alt:auto;mso-m=
argin-bottom-alt:
       auto;text-align:left;mso-pagination:widow-orphan;mso-list:l2 level1 =
lfo3;
       tab-stops:list 36.0pt'><span lang=3DEN-US style=3D'font-size:9.0pt;
       font-family:Verdana;mso-bidi-font-family:SimSun;mso-font-kerning:0pt=
'>Hint
       2. A catfish cannot mate with itself! So, check if the mate is a </s=
pan><span
       lang=3DEN-US style=3D'font-size:12.0pt;font-family:SimSun;mso-bidi-f=
ont-family:
       SimSun;mso-font-kerning:0pt'>Catfish</span><span lang=3DEN-US
       style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:Si=
mSun;
       mso-font-kerning:0pt'> object and is different from the catfish obje=
ct
       that is looking for a mate. Make use of the fact that each catfish h=
as a
       unique name. <o:p></o:p></span></li>
   <li class=3DMsoNormal style=3D'color:black;mso-margin-top-alt:auto;mso-m=
argin-bottom-alt:
       auto;text-align:left;mso-pagination:widow-orphan;mso-list:l2 level1 =
lfo3;
       tab-stops:list 36.0pt'><span lang=3DEN-US style=3D'font-size:9.0pt;
       font-family:Verdana;mso-bidi-font-family:SimSun;mso-font-kerning:0pt=
'>Hint
       3. A mate must be at least 10 time blocks old. <o:p></o:p></span></l=
i>
  </ul>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;text-align:left;mso-pagination:widow-orphan'><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>Observe how the </span><span lang=3DEN-=
US
  style=3D'font-size:12.0pt;font-family:SimSun;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>findMate</span><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'> method is called from the </span><span
  lang=3DEN-US style=3D'font-size:12.0pt;font-family:SimSun;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'>mateIfPossible</span><span
  lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-f=
amily:
  SimSun;color:black;mso-font-kerning:0pt'> method.<o:p></o:p></span></p>
  <ul type=3Ddisc>
   <li class=3DMsoNormal style=3D'color:black;mso-margin-top-alt:auto;mso-m=
argin-bottom-alt:
       auto;text-align:left;mso-pagination:widow-orphan;mso-list:l5 level1 =
lfo4;
       tab-stops:list 36.0pt'><span lang=3DEN-US style=3D'font-size:12.0pt;
       font-family:SimSun;mso-bidi-font-family:SimSun;mso-font-kerning:0pt'=
>findMate</span><span
       lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-f=
ont-family:
       SimSun;mso-font-kerning:0pt'> should return </span><span lang=3DEN-US
       style=3D'font-size:12.0pt;font-family:SimSun;mso-bidi-font-family:Si=
mSun;
       mso-font-kerning:0pt'>null</span><span lang=3DEN-US style=3D'font-si=
ze:9.0pt;
       font-family:Verdana;mso-bidi-font-family:SimSun;mso-font-kerning:0pt=
'>
       if no mates are found. <o:p></o:p></span></li>
   <li class=3DMsoNormal style=3D'color:black;mso-margin-top-alt:auto;mso-m=
argin-bottom-alt:
       auto;text-align:left;mso-pagination:widow-orphan;mso-list:l5 level1 =
lfo4;
       tab-stops:list 36.0pt'><span lang=3DEN-US style=3D'font-size:12.0pt;
       font-family:SimSun;mso-bidi-font-family:SimSun;mso-font-kerning:0pt'=
>findMate</span><span
       lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-f=
ont-family:
       SimSun;mso-font-kerning:0pt'> should return a mate (a </span><span
       lang=3DEN-US style=3D'font-size:12.0pt;font-family:SimSun;mso-bidi-f=
ont-family:
       SimSun;mso-font-kerning:0pt'>Catfish</span><span lang=3DEN-US
       style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:Si=
mSun;
       mso-font-kerning:0pt'> object) if a mate is found. <o:p></o:p></span=
></li>
  </ul>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;text-align:left;mso-pagination:widow-orphan'><span lang=3DEN-US
  style=3D'font-size:9.0pt;font-family:Verdana;mso-bidi-font-family:SimSun;
  color:black;mso-font-kerning:0pt'>Applying the process taught earlier in =
this
  course, here's a list of steps you might take to complete this assessment=
. As
  you do, be sure to work and test incrementally &#8212; and save your work
  often. <o:p></o:p></span></p>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;margin-left:36.0pt;text-align:left;text-indent:-18.0pt;mso-paginatio=
n:
  widow-orphan;mso-list:l1 level1 lfo5;tab-stops:list 36.0pt'><![if !suppor=
tLists]><span
  lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-fareast-fon=
t-family:
  Verdana;mso-bidi-font-family:Verdana;color:black;mso-font-kerning:0pt'><s=
pan
  style=3D'mso-list:Ignore'>1.<span style=3D'font:7.0pt "Times New Roman"'>=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
  </span></span></span><![endif]><span lang=3DEN-US style=3D'font-size:9.0p=
t;
  font-family:Verdana;mso-bidi-font-family:SimSun;color:black;mso-font-kern=
ing:
  0pt'>Design your method by stating, in English, the sequence of activities
  your method should perform. <o:p></o:p></span></p>
  <p class=3DMsoNormal align=3Dleft style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:
  auto;margin-left:36.0pt;text-align:left;text-indent:-18.0pt;mso-paginatio=
n:
  widow-orphan;mso-list:l1 level1 lfo5;tab-stops:list 36.0pt'><![if !suppor=
tLists]><span
  lang=3DEN-US style=3D'font-size:9.0pt;font-family:Verdana;mso-fareast-fon=
t-family:
  Verdana;mso-bidi-font-family:Verdana;color:black;mso-font-kerning:0pt'><s=
pan
  style=3D'mso-list:Ignore'>2.<span style=3D'font:7.0pt "Times New Roman"'>=