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[QUOTE="Alf P. Steinbach /Usenet, post: 4119870"]
* Öö Tiib, on 22.08.2010 04:09:

"Exit" is a special command because it needs handling at the level that calls 
'doCommand'. That level has to stop looping. In your code you're thinking about 
'doCommand' perhaps asking the user to confirm, but you stop looping anyway...

So, you can either special-case the signature of 'doCommand' to support "Exit", 
or you can just handle it directly. Special-casing is problematic because there 
can be two or three such special cases.

It's the KISS principle, Keep It Simple.

You might alternatively consider the weaker example

double  sum     = 0.0;

cout << explanation << endl;
     for( ;; )
     {
         double const number = numberFromUser( "Number? " );

if( number == 0.0 ) { break; }
         sum += number;
     }

But in a way it accentuates the issue because here it's a least plausible to put 
both the input operation and checking as a 'while' loop condition.

To my eyes the 'while', with side-effect condition, obfuscates what the effect 
of the code is, sort of compiling it down to a lower level language, needlessly 
extends the scope of a variable, and makes it more difficult to introduce 
changes, i.e. reduced maintainability.

Cheers & hth.,

- Alf
[/QUOTE]

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