[Tutor] newbie-class differs from function?
alan.gauld@bt.com
alan.gauld@bt.com
Mon Mar 10 12:31:46 2003
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> ... understood the difference, in hyper-simple terms, between
> a class and a conventional, programmer defined function.
A function is a block of executable code that may take parameters and return
a value.
A class is a collection of data and functions that operate on the data - all
wrapped
up in a single bundle.
You can create a class which only contains functions(known as methods in OO
speak)
and then call those methods via the class. If you do that there is no real
advantage
over conventional functions - Java does this a lot...
Real OOP comes when you create multiple instances of a class. Each can have
its
own set of iinternal data values and they share a common set of methods. The
instances become like little mini processes which communicate with each
other.
For more information and examples look at my web tutor under the OOP
section.
Alan g.
Author of the Learn to Program website
http://www.freenetpages.co.uk/hp/alan.gauld/
<http://www.freenetpages.co.uk/hp/alan.gauld/>
PS
The web site was down again at the weekend but is back up again now.
Dunno what's happening with freenet just now!
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<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff
size=2> > ... </FONT></SPAN>understood the difference, in
hyper-simple terms, between<SPAN class=608592317-10032003><FONT face=Arial
color=#0000ff size=2> </FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>>
</FONT> </SPAN>a class and a conventional, programmer defined
function.<SPAN class=608592317-10032003><FONT face=Arial color=#0000ff
size=2> </FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>A
function is a block of executable code that may take parameters and return a
value.</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>A
class is a collection of data and functions that operate on the data - all
wrapped </FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>up in
a single bundle.</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>You
can create a class which only contains functions(known as methods in OO speak)
</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>and
then call those methods via the class. If you do that there is no real
advantage</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>over
conventional functions - Java does this a lot...</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>Real
OOP comes when you create multiple instances of a class. Each can have its
</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>own
set of iinternal data values and they share a common set of methods. The
</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff
size=2>instances become like little mini processes which communicate with each
other.</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>For
more information and examples look at my web tutor under the OOP
section.</FONT></SPAN></DIV><SPAN class=608592317-10032003>
<P><FONT face="Courier New" size=2>Alan g.</FONT> <BR><FONT face="Courier New"
size=2>Author of the Learn to Program website</FONT> <BR><FONT
face="Courier New" size=2><A target=_blank
href="http://www.freenetpages.co.uk/hp/alan.gauld/">http://www.freenetpages.co.uk/hp/alan.gauld/</A></FONT>
</P>
<DIV><FONT face=Arial color=#0000ff size=2></FONT> </DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>PS
</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>The
web site was down again at the weekend but is back up again
now.</FONT></SPAN></DIV>
<DIV><SPAN class=608592317-10032003><FONT face=Arial color=#0000ff size=2>Dunno
what's happening with freenet just now!</FONT></SPAN></SPAN></DIV></BODY></HTML>
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