<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<!--[if !mso]>
<style>
v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style>
<![endif]-->
<style>
<!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
@font-face
{font-family:"Segoe UI";
panose-1:2 11 5 2 4 2 4 2 2 3;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-believe-normal-left:yes;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
{mso-style-priority:99;
mso-style-link:"Plain Text Char";
margin:0cm;
margin-bottom:.0001pt;
font-size:10.5pt;
font-family:Consolas;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0cm;
mso-margin-bottom-alt:auto;
margin-left:0cm;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.PlainTextChar
{mso-style-name:"Plain Text Char";
mso-style-priority:99;
mso-style-link:"Plain Text";
font-family:Consolas;}
span.EmailStyle20
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle21
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle23
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page Section1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.Section1
{page:Section1;}
-->
</style>
<![if mso 9]>
<style>
p.MsoNormal
{margin-left:3.0pt;}
</style>
<![endif]><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-AU link=blue vlink=purple style='margin-left:3.0pt;margin-top:
3.0pt;margin-right:3.0pt;margin-bottom:.75pt'>
<div class=Section1>
<p class=MsoNormal><span style='color:#1F497D'>Hi Maggie (and all),<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>You raise a good point. I am clarifying
selected items with VCAA so that what I write is as close to what is expected
as possible. As there is only going to be 1 text, I am conscious of this and I
know that there is the potential for the text to set the ‘tone’
with students and has to be in line with the study. The text is being
professionally edited and will be peer reviewed by at least 2 of my colleagues.
Additions to the study I am running by Paula and others just to make sure.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Cheers,<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Adrian<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<p class=MsoNormal><b><span style='font-size:18.0pt;font-family:"Times New Roman","serif";
color:#002060'>Adrian Janson </span></b><b><span style='font-size:7.0pt;
font-family:"Times New Roman","serif";color:#002060'>B.Sc, Dip.Ed, M.Ed<br>
</span></b><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif";
color:#002060'>Director of ICT<br>
</span></b><span style='font-size:12.0pt;font-family:"Times New Roman","serif";
color:#244061'>Melbourne High School, Forrest Hill, South Yarra, Victoria 3141
Australia.<br>
Phone: 03 9826 0711 International: +61 3 9826 0711<br>
Fax: 03 9826 8767 International: +61 3 9826 8767<br>
E-mail: <a href="janson.adrian.a@edumail.vic.gov.au">janson.adrian.a@edumail.vic.gov.au</a><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";
color:#244061'>Website: <a href="http://www.mhs.vic.edu.au/">http://www.mhs.vic.edu.au</a></span><span
style='color:black'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";
color:#244061'>Blog: <a href="http://jansona.edublogs.org/" target="_blank">http://jansona.edublogs.org</a></span><span
style='color:black'><o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> sofdev-bounces@edulists.com.au
[mailto:sofdev-bounces@edulists.com.au] <b>On Behalf Of </b>Margaret Iaquinto<br>
<b>Sent:</b> Thursday, 19 August 2010 12:10 PM<br>
<b>To:</b> List', 'Year 12 Software Development Teachers' Mailing<br>
<b>Subject:</b> Re: [Year 12 SofDev] Records and Arrays<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>Your
textbook will be very handy to have, Adrian, but if the examinations panel
members do not agree with your definition, then we are all in deep yoghurt.<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>Maggie<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<div>
<p class=MsoNormal><strong><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>Margaret
Iaquinto</span></strong><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>Information
Technology Coordinator<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>St
Leonard's College<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>Brighton
Campus<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>t
(+61 3) 9909 9300<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>x 529<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'><a
href="http://www.stleonards.vic.edu.au/">www.stleonards.vicedu.au</a><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'><img
border=0 width=160 height=48 id="_x0000_i1025"
src="cid:image001.png@01CB3F99.FE7A5F90"><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>Alternate
email: <a href="mailto:maggie@iaquinto.net">maggie@iaquinto.net</a><o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'><br>
<br>
>>> Adrian Janson <janson.adrian.a@edumail.vic.gov.au>
19/08/2010 11:30 AM >>><o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='color:#1F497D'>Hmm... the definition from
Wikipedia also does not include a reference to arrays needing to be the same
type:<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN>In <a
href="http://en.wikipedia.org/wiki/Computer_science" title="Computer science">computer
science</a>, an <b>array data structure</b> or simply <b>array</b> is a <a
href="http://en.wikipedia.org/wiki/Data_structure" title="Data structure">data
structure</a> consisting of a collection of <i>elements</i> (<a
href="http://en.wikipedia.org/wiki/Value_(computer_science)"
title="Value (computer science)">values</a> or <a
href="http://en.wikipedia.org/wiki/Variable_(programming)"
title="Variable (programming)">variables</a>), each identified by one or more <a
href="http://en.wikipedia.org/wiki/Integer_(computer_science)"
title="Integer (computer science)">integer</a> <i><a
href="http://en.wikipedia.org/wiki/Index_(information_technology)"
title="Index (information technology)">indices</a></i>, stored so that the <a
href="http://en.wikipedia.org/wiki/Physical_address" title="Physical address">address</a>
of each element can be computed from its index <a
href="http://en.wikipedia.org/wiki/Tuple" title=Tuple>tuple</a> by a simple
mathematical formula.<sup id="cite_ref-0"><a
href="http://en.wikipediaorg/wiki/Array_data_structure#cite_note-0">[1]</a><a
href="http://en.wikipedia.org/wiki/Array_data_structure#cite_note-knuth-1">[2]</a></sup>
For example, an array of 10 integer variables, with indices 0 through 9, may be
stored as 10 <a href="http://en.wikipedia.org/wiki/Word_(computing)"
title="Word (computing)">words</a> at memory addresses 2000, 2004, 2008, . 2036
(this memory allocation can vary because some computers use other than 4 bytes
to store integer type variables); so that the element with index <i>i</i> has
address 2000 + 4 × <i>i</i>.<sup id="cite_ref-2"><a
href="http://en.wikipedia.org/wiki/Array_data_structure#cite_note-2">[3]</a></sup></span><span
style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>I will change my definition and
remove the reference to variable type. I will also not talk about
'strongly typed languages' etc - as will definitely cause confusion. The
ultimate goal of the text is to support the study - and as such does need to
state a definition that students would be expected to know - teachers can then
provide the icing on this cake. Guy - your breakdown of arrays/records in
different languages is great - and it may be that we share some materials that
flesh out these points. In the context of the text again, adding this
sort of detail will probably add to confusion. <o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Cheers,<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Adrian<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<p class=MsoNormal><b><span style='font-size:18.0pt;font-family:"Times New Roman","serif";
color:#002060'>Adrian Janson </span></b><b><span style='font-size:7.0pt;
font-family:"Times New Roman","serif";color:#002060'>B.Sc, Dip.Ed, M.Ed<br>
</span></b><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif";
color:#002060'>Director of ICT<br>
</span></b><span style='font-size:12.0pt;font-family:"Times New Roman","serif";
color:#244061'>Melbourne High School, Forrest Hill, South Yarra, Victoria 3141
Australia.<br>
Phone: 03 9826 0711 International: +61 3 9826 0711<br>
Fax: 03 9826 8767 International: +61 3 9826 8767<br>
E-mail: <a href="janson.adrian.a@edumail.vic.gov.au">janson.adrian.a@edumail.vic.gov.au</a><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";
color:#244061'>Website: <a href="http://www.mhs.vic.edu.au/">http://www.mhs.vic.edu.au</a></span><span
style='color:black'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";
color:#244061'>Blog: <a href="http://jansona.edublogs.org/" target="_blank">http://jansona.edublogs.org</a></span><span
style='color:black'><o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> sofdev-bounces@edulists.com.au [mailto:sofdev-bounces@edulists.com.au]
<b>On Behalf Of </b>Laurie Savage<br>
<b>Sent:</b> Thursday, 19 August 2010 10:32 AM<br>
<b>To:</b> 'Year 12 Software Development Teachers' Mailing List'<br>
<b>Subject:</b> Re: [Year 12 SofDev] Records and Arrays<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='color:#1F497D'>I'm sorry, but "</span><span
lang=EN-US>an array has to contain elements all of the same type"</span><span
style='color:#1F497D'> is neither generally nor necessarily true so should not
be taught</span><span lang=EN-US>. When I teach Physics I do not teach the
Geocentric model, and in Geology I do not teach the Biblical flood. Why?
Because they are neither useful nor predictive and are refuteable.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Laurie</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> sofdev-bounces@edulists.com.au
[mailto:sofdev-bounces@edulists.com.au] <b>On Behalf Of </b>Adrian Janson<br>
<b>Sent:</b> Thursday, 19 August 2010 10:01 AM<br>
<b>To:</b> 'Year 12 Software Development Teachers' Mailing List'<br>
<b>Subject:</b> Re: [Year 12 SofDev] Records and Arrays<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoPlainText>Hi everyone,<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>As the one writing the text book for 2011+, here is what
I have written for the definitions of array and record (there is more detail
and examples following these definitions):<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><b>One-Dimensional Arrays<o:p></o:p></b></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify'>A one dimensional (or 1D) array
is a data structure in which variables of the same type are grouped together
under the same name. <o:p></o:p></p>
<p class=MsoNormal style='text-align:justify'>...<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify'><o:p> </o:p></p>
<p class=MsoNormal><b>Records<o:p></o:p></b></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-US>A record is a structure that can be used to
group together a variety of information for a particular purpose. Records
are similar to arrays but whereas an array has to contain elements all of the
same type, the variables within a record can be of different types.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoPlainText>...<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>I do think that there is a place for a standard
definition - as students will probably not use 1 language in their lives
(assuming that they progress to an IT course of some description), and even if
they don't, the standard definition can set a context for a discussion of how
the language differs from this (if it is not strongly typed). I don't
think it would hurt to say 'the definition of an array is XYZ, however in PHP,
an array works in this way....' Interesting to note that there are 6
languages for which the definitions above do not strictly hold! <o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Is the concensus of this community that you would like me
to include more in these definitions about the distinction of strongly typed
languages? Or what is the general feeling about the definitions that I
have written above?<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Cheers,<o:p></o:p></p>
<p class=MsoPlainText>Adrian<o:p></o:p></p>
<p class=MsoNormal><b><span style='font-size:18.0pt;font-family:"Times New Roman","serif";
color:#002060'><o:p> </o:p></span></b></p>
<p class=MsoNormal><b><span style='font-size:18.0pt;font-family:"Times New Roman","serif";
color:#002060'>Adrian Janson </span></b><b><span style='font-size:7.0pt;
font-family:"Times New Roman","serif";color:#002060'>B.Sc, Dip.Ed, M.Ed<br>
</span></b><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif";
color:#002060'>Director of ICT<br>
</span></b><span style='font-size:12.0pt;font-family:"Times New Roman","serif";
color:#244061'>Melbourne High School, Forrest Hill, South Yarra, Victoria 3141
Australia.<br>
Phone: 03 9826 0711 International: +61 3 9826 0711<br>
Fax: 03 9826 8767 International: +61 3 9826 8767<br>
E-mail: <a href="janson.adrian.a@edumail.vic.gov.au">janson.adrian.a@edumail.vic.gov.au</a><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";
color:#244061'>Website: <a href="http://www.mhs.vic.edu.au/">http://www.mhs.vic.edu.au</a></span><span
style='color:black'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";
color:#244061'>Blog: <a href="http://jansona.edublogs.org/" target="_blank">http://jansona.edublogs.org</a></span><span
style='color:black'><o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-US>-----Original Message-----<br>
From: sofdev-bounces@edulists.com.au [mailto:sofdev-bounces@edulists.com.au] On
Behalf Of Laurie Savage<br>
Sent: Thursday, 19 August 2010 9:23 AM<br>
To: 'Year 12 Software Development Teachers' Mailing List'<br>
Subject: Re: [Year 12 SofDev] Records and Arrays</span><o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Guy,<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>You are right, and of course I have taught this
distinction. As I mentioned<o:p></o:p></p>
<p class=MsoPlainText>to Maggie, I do object to teaching things that students
need to unlearn or<o:p></o:p></p>
<p class=MsoPlainText>that are irrelevant.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Laurie<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>-----Original Message-----<o:p></o:p></p>
<p class=MsoPlainText>From: sofdev-bounces@edulists.com.au
[mailto:sofdev-bounces@edulists.com.au]<o:p></o:p></p>
<p class=MsoPlainText>On Behalf Of Guy Flaherty<o:p></o:p></p>
<p class=MsoPlainText>Sent: Thursday, 19 August 2010 9:19 AM<o:p></o:p></p>
<p class=MsoPlainText>To: 'Year 12 Software Development Teachers' Mailing List'<o:p></o:p></p>
<p class=MsoPlainText>Subject: Re: [Year 12 SofDev] Records and Arrays<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Laurie,<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Typing is not really the issue, and Steven's explanation
is quite likely to<o:p></o:p></p>
<p class=MsoPlainText>cause more confusion in my opinion. Let me explain my
thinking:<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>The difference between a record and an array is simply
that one allows only<o:p></o:p></p>
<p class=MsoPlainText>one type of data to be used, the other allows multiple
types of data to be<o:p></o:p></p>
<p class=MsoPlainText>used (some languages require type to be declared, others
don't).<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Associative 'arrays' are called 'arrays' in their
language literature, but<o:p></o:p></p>
<p class=MsoPlainText>according to the study design they are in fact 'records'
and not 'arrays'.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Java does not even have a record type, you have to create
a class with no<o:p></o:p></p>
<p class=MsoPlainText>instance methods to represent a 'record' type, so now you
have to include<o:p></o:p></p>
<p class=MsoPlainText>classes if you start thinking about Java. Additionally,
other languages,<o:p></o:p></p>
<p class=MsoPlainText>such as PHP, Python, Ruby etc can do the same thing as
Java but are not<o:p></o:p></p>
<p class=MsoPlainText>required to as their 'array' types can work as 'arrays'
or 'records'.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Ruby names their 'record' type an 'array' and their
'associative array' a<o:p></o:p></p>
<p class=MsoPlainText>'hash', making it even more difficult for students
learning Ruby to<o:p></o:p></p>
<p class=MsoPlainText>understand the Study Design definitions.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Thinking about all this, I am simply going to instruct my
students that for<o:p></o:p></p>
<p class=MsoPlainText>the purpose of completing any exam questions, the
difference between a<o:p></o:p></p>
<p class=MsoPlainText>record and an array IS that one can contain multiple
types of data and the<o:p></o:p></p>
<p class=MsoPlainText>other can only contain one type of data. Despite the fact
that this is not<o:p></o:p></p>
<p class=MsoPlainText>what they are seeing when they do their programming, this
is how it would<o:p></o:p></p>
<p class=MsoPlainText>seem to be best to approach it.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Guy Flaherty<o:p></o:p></p>
<p class=MsoPlainText> <o:p></o:p></p>
<p class=MsoPlainText>>>> "Laurie Savage"
<savage.john.l@edumail.vic.gov.au> 19/08/10 08:39 AM >>><o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Well yes, and no. Thanks for the very clear description
of a record which IS<o:p></o:p></p>
<p class=MsoPlainText>an array (is ISBN an integer or a string? PHP will treat
it contextually)!<o:p></o:p></p>
<p class=MsoPlainText>However this does not take away from the fact that some
major modern<o:p></o:p></p>
<p class=MsoPlainText>languages are not strongly typed and so the study guide
distinction does not<o:p></o:p></p>
<p class=MsoPlainText>apply and this disadvantages students working in those
languages.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText> <o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Laurie<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText> <o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>From: sofdev-bounces@edulists.com.au
[mailto:sofdev-bounces@edulists.com.au]<o:p></o:p></p>
<p class=MsoPlainText>On Behalf Of Steven Bird<o:p></o:p></p>
<p class=MsoPlainText>Sent: Wednesday, 18 August 2010 8:58 PM<o:p></o:p></p>
<p class=MsoPlainText>To: Year 12 Software Development Teachers' Mailing List<o:p></o:p></p>
<p class=MsoPlainText>Subject: Re: [Year 12 SofDev] Records and Arrays<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText> <o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>The following might help you to distinguish these
concepts.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Consider any kind of real world entity, e.g. a student, a
school, a book, a<o:p></o:p></p>
<p class=MsoPlainText>patient, etc. Now think about its attributes.
For a book this might be<o:p></o:p></p>
<p class=MsoPlainText>title, author, year, isbn, price... When we model such
an entity using a<o:p></o:p></p>
<p class=MsoPlainText>computer, we specify a set of attributes. This is a
"record". It is just a<o:p></o:p></p>
<p class=MsoPlainText>collection of attributes describing an entity.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>A record could be stored on disk (e.g. as a row of a
relational database<o:p></o:p></p>
<p class=MsoPlainText>table, or as a row of a CSV file), or represented in
volatile memory in a<o:p></o:p></p>
<p class=MsoPlainText>data structure in a running program. Perhaps the
most common data type used<o:p></o:p></p>
<p class=MsoPlainText>for representing a record is an "associative
array" ("hash" in Perl;<o:p></o:p></p>
<p class=MsoPlainText>"dictionary" in Python; "array" (!)
in PHP, "map" in C++); some languages<o:p></o:p></p>
<p class=MsoPlainText>support a "tuple" type which is also
appropriate for representing records.<o:p></o:p></p>
<p class=MsoPlainText>However, at one level these details don't matter.
What's important is just<o:p></o:p></p>
<p class=MsoPlainText>that we have a set of attributes.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Now consider any collection of entities of the same type,
e.g. students,<o:p></o:p></p>
<p class=MsoPlainText>schools, books, patients, etc. When we model these
in a computer, we<o:p></o:p></p>
<p class=MsoPlainText>specify a collection of like entities. This is just
a set or list of<o:p></o:p></p>
<p class=MsoPlainText>entities.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>This list could be stored on disk (e.g. as a relational
table, or a CSV<o:p></o:p></p>
<p class=MsoPlainText>file), or represented in a running program. The
most common data type is an<o:p></o:p></p>
<p class=MsoPlainText>"array", and that's what it is called in most
languages (but it is "list" in<o:p></o:p></p>
<p class=MsoPlainText>Python). Some languages encourage you to define
array elements to be all of<o:p></o:p></p>
<p class=MsoPlainText>the same type, but not all. In general, I think
this is a good practice.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>PHP blurs the distinction between records and
arrays. However, a programmer<o:p></o:p></p>
<p class=MsoPlainText>can use PHP in such a way to keep them quite distinct:<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>my_record1 = array('isbn'=>1441412050,
'title'=>'Alice in Wonderland',<o:p></o:p></p>
<p class=MsoPlainText>'author'=>'Lewis Carroll');<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>my_record2 = array('isbn'=>1441412050,
'title'=>'Through the Looking Glass',<o:p></o:p></p>
<p class=MsoPlainText>'author'=>'Lewis Carroll');<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>my_array = array(my_record1, my_record2);<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>my_record1['isbn']; /* access a record's
attribute by name */ <o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>my_array[1];
/* access an array's element by index */<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>I hope this helps!<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>--<o:p></o:p></p>
<p class=MsoPlainText>Steven Bird<o:p></o:p></p>
<p class=MsoPlainText>http://stevenbird.me/<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Important - This email and any attachments may be
confidential. If received<o:p></o:p></p>
<p class=MsoPlainText>in error, please contact us and delete all copies Before
opening or using<o:p></o:p></p>
<p class=MsoPlainText>attachments check them for viruses and defects.
Regardless of any loss,<o:p></o:p></p>
<p class=MsoPlainText>damage or consequence, whether caused by the negligence
of the sender or<o:p></o:p></p>
<p class=MsoPlainText>not, resulting directly or indirectly from the use of any
attached files our<o:p></o:p></p>
<p class=MsoPlainText>liability is limited to resupplying any affected
attachments. Any<o:p></o:p></p>
<p class=MsoPlainText>representations or opinions expressed are those of the
individual sender,<o:p></o:p></p>
<p class=MsoPlainText>and not necessarily those of the Department of Education
and Early Childhood<o:p></o:p></p>
<p class=MsoPlainText>Development.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Scanned by Sonar. <o:p></o:p></p>
<p class=MsoPlainText>Date: 2010-08-19 08:45:37.693<o:p></o:p></p>
<p class=MsoPlainText>From: sofdev-bounces@edulists.com.au<o:p></o:p></p>
<p class=MsoPlainText>To: g.flaherty@xavier.vic.edu.au<o:p></o:p></p>
<p class=MsoPlainText>Profile: Default_In<o:p></o:p></p>
<p class=MsoPlainText>Mail id: challenge-2171534856i43-0<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>"This email and any files transmitted with it are
confidential and intended<o:p></o:p></p>
<p class=MsoPlainText>solely for the use of the individual or entity to whom
they are addressed.<o:p></o:p></p>
<p class=MsoPlainText>If you have received this email in error please notify
the Network Manager<o:p></o:p></p>
<p class=MsoPlainText>at Xavier College. Please note that any views or opinions
presented in this<o:p></o:p></p>
<p class=MsoPlainText>email are solely those of the author and do not
necessarily represent those<o:p></o:p></p>
<p class=MsoPlainText>of Xavier College. Whilst every attempt has been made to
ensure material in<o:p></o:p></p>
<p class=MsoPlainText>this email message is free from computer viruses or other
defects, the<o:p></o:p></p>
<p class=MsoPlainText>attached files are provided, and may only be used, on the
basis that the<o:p></o:p></p>
<p class=MsoPlainText>user assumes all responsibility for the use of the
material transmitted."<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>_______________________________________________<o:p></o:p></p>
<p class=MsoPlainText>http://www.edulists.com.au - FAQ, Subscribe, Unsubscribe<o:p></o:p></p>
<p class=MsoPlainText>IT Software Development Mailing List kindly supported by<o:p></o:p></p>
<p class=MsoPlainText>http://www.vcaa.vic.edu.au - Victorian Curriculum and
Assessment Authority<o:p></o:p></p>
<p class=MsoPlainText>and<o:p></o:p></p>
<p class=MsoPlainText>http://www.vcaa.vic.edu.au/vce/studies/infotech/softwaredevel3-4.html
<o:p></o:p></p>
<p class=MsoPlainText>http://www.vitta.org.au - VITTA Victorian Information
Technology Teachers<o:p></o:p></p>
<p class=MsoPlainText>Association Inc<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Important - This email and any attachments may be
confidential. If received in error, please contact us and delete all copies.
Before opening or using attachments check them for viruses and defects.
Regardless of any loss, damage or consequence, whether caused by the negligence
of the sender or not, resulting directly or indirectly from the use of any
attached files our liability is limited to resupplying any affected
attachments. Any representations or opinions expressed are those of the
individual sender, and not necessarily those of the Department of Education and
Early Childhood Development.<o:p></o:p></p>
<p class=MsoPlainText>_______________________________________________<o:p></o:p></p>
<p class=MsoPlainText>http://www.edulists.com.au - FAQ, Subscribe, Unsubscribe<o:p></o:p></p>
<p class=MsoPlainText>IT Software Development Mailing List kindly supported by<o:p></o:p></p>
<p class=MsoPlainText>http://www.vcaa.vic.edu.au - Victorian Curriculum and
Assessment Authority and<o:p></o:p></p>
<p class=MsoPlainText>http://www.vcaa.vic.edu.au/vce/studies/infotech/softwaredevel3-4.html
<o:p></o:p></p>
<p class=MsoPlainText>http://www.vitta.org.au - VITTA Victorian
Information Technology Teachers Association Inc<o:p></o:p></p>
<p><b>Important - </b>This email and any attachments may be confidential. If
received in error, please contact us and delete all copies. Before opening or
using attachments check them for viruses and defects. Regardless of any loss,
damage or consequence, whether caused by the negligence of the sender or not,
resulting directly or indirectly from the use of any attached files our
liability is limited to resupplying any affected attachments. Any
representations or opinions expressed are those of the individual sender, and
not necessarily those of the Department of Education and Early Childhood
Development.<o:p></o:p></p>
<p><b>Important - </b>This email and any attachments may be confidential. If
received in error, please contact us and delete all copies. Before opening or
using attachments check them for viruses and defects. Regardless of any loss,
damage or consequence, whether caused by the negligence of the sender or not,
resulting directly or indirectly from the use of any attached files our
liability is limited to resupplying any affected attachments. Any
representations or opinions expressed are those of the individual sender, and
not necessarily those of the Department of Education and Early Childhood
Development.<o:p></o:p></p>
<p><b>Important - </b>This email and any attachments may be confidential. If
received in error, please contact us and delete all copies. Before opening or
using attachments check them for viruses and defects. Regardless of any loss,
damage or consequence, whether caused by the negligence of the sender or not, resulting
directly or indirectly from the use of any attached files our liability is
limited to resupplying any affected attachments. Any representations or
opinions expressed are those of the individual sender, and not necessarily
those of the Department of Education and Early Childhood Development.<o:p></o:p></p>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>CAUTION
- </span></b><span style='font-size:10.0pt;font-family:"Segoe UI","sans-serif"'>This
message may contain privileged and confidential information intended only for
the use of the addressee named above. If you are not the intended recipient of
this message you are hereby notified that any use, dissemination, distribution
or reproduction of this message is prohibited. If you have received this
message in error please notify St Leonard's College immediately. Any views
expressed in this message are those of the individual sender and may not
necessarily reflect the views of St Leonard's College. <o:p></o:p></span></p>
</div>
<p></p><p><b>Important - </b>This email and any attachments may be confidential. If received in error, please contact us and delete all copies. Before opening or using attachments check them for viruses and defects. Regardless of any loss, damage or consequence, whether caused by the negligence of the sender or not, resulting directly or indirectly from the use of any attached files our liability is limited to resupplying any affected attachments. Any representations or opinions expressed are those of the individual sender, and not necessarily those of the Department of Education and Early Childhood Development.</p>
</body>
</html>