Re: for loops

IF you are expecting the user to actually log in by typing in some
infromation, then speed is irrelevant since it is strictly in the user's
hands.

I heard the same lecture from a professor. Don't jump out of the code in the
middle.

I personally would never use a FOR ENDFOR loop for something that I do not
always expect to run a specified number of times. For a variable situation
such as you are suggesting, I would always use a WHILE loop. As for there
being more code lines or slower execution of a while loop vs a for loop, why
would a good programmer care. Good programming is about clarity and
reliability.


The following general structure has served me well in over fifty apps.

************ Start of main procedure
lsuccess = .F.
cntr = 1
DO WHILE !lsuccess and cntr <= 3
cntr = cntr + 1
lsuccess = <login_procedure>
ENDDO
IF lsuccesss
< run app here >
ELSE
= MESSAGEBOX("Not allowed In",16,"Login Error")
ENDIF

************* End of Main procedure


"Carsten Bonde" wrote:

> Andrew,
>
> a prof. at the university where i studied once said, using EXIT, "DO WHILE
> ..T." and such constructs lets one think the programmer wasnt able to create
> a proper termination of his loops. A statement i always kept in mind,
> regardless of which programming-language i worked in.
>
> If speed is important, there actually may be situations where one may break
> his own rules. Indeed a good point, thank you.
>
> Using EXIT (or LOOP) breaks the structured program-flow. Sometimes small
> procedures grows up to real big ones, now facing an EXIT or LOOP in line 258
> most likely confuses any person who didn't write the code (and even the
> author 2 years later <gg>).
>
> Anyway - using welldefine termination of loops, or the easy "EXIT"-way might
> be a matter of taste.
>
> --
> Cheers
> Carsten
> _______________________________
>
> "Andrew Howell" <ajh@work> schrieb im Newsbeitrag
> news:ecpE5x2GGHA.2300@xxxxxxxxxxxxxxxxxxxxxxx
> > "Carsten Bonde" <bonde AT real-inkasso DOT de> wrote in message
> > news:uiTfLq0GGHA.344@xxxxxxxxxxxxxxxxxxxxxxx
> >> Beside that, i wouldnt use a FOR ENDFOR-construct, but a WHILE since you
> >> should exit when the user enters a correct password. Using "EXIT" is in
> >> my opinion NOT an option <s>
> >
> > I'm with you in principle but there *are* more lines of code for an
> > equivalent WHILE and it does execute slower (I guess most likely because
> > your increment happens in Fox rather than C.) It's unlikely the speed gain
> > would be beneficial really (in any routine,) I'm just saying... <g>
> >
> > I've used FOR with EXIT for simple loops, eg checking a string for any
> > alpha characters present (as soon as you hit one, may as well EXIT.)
> > Although even that was before I knew how to do it with CHRTRAN.
> > I've always hated DO WHILE .T. more than FOR..EXIT..NEXT - I guess because
> > the construct is already waiting for a flag but for all that, why does
> > EXIT exist? To not be used? <s>
> >
> > --
> > Regards
> > Andrew Howell
> >
>
>
>
.

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