[Tutor] Communication between classes

[Alan Gauld]

"Greg Perry" <gregp at liveammo.com> wrote 

> That makes sense, thank you for the detailed explanation 
> Andrei.  For this simple project I am working on, it looks 
> like the most direct route would be to use functions 

Thats often the case. Often when people start with OOP 
they try to do everything with objects. Its possible but often 
not very efficient.

> and only develop classes for the portions of the program 
> that can be reused.
> Is it safe to say that classes are only useful for instances 
> where reuse is a key consideration?  

Its not only for reuse. Classes and objects are often a 
more natural model of the real world. One of the best 
examples is a GUI program where each window or control 
can be treated as an object. Thats intuitively obvious because 
to our eyews it looks and acts somewhat like a real world 
object. But you rarely reuse the specific controls or windows 
developeed for a particular project. (Widgets are another 
matter, they are designed for reuse)

> seems that classes are in most cases overkill for simple 
> tasks 

Yes thats true. OOP was invented as a way to control 
complexity in large programs. It can be used in smaller 
programs but if you only have a dozen or so linres of 
executable code then classes may well be overkill.

> such as reading the command line then calculating a 
> hash/checksum to verify integrity

If you had a lot of different data types each with their own 
checksum algorithm then classes and objects might be 
appropriate but a single case would usually be easier 
using functions.

HTH,

-- 
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld