var i , n : integer;
for i := 1 to 100 do begin
    if IntArray[i] > 100 then  begin
     n := i;
     break;
    end;
end;
writeln('The '+IntToStr(i)+' item in the array > 100');
//can we be always sure the value i is always the same as n?
Even when the compiler optimizes it and uses a cpu register for i
instead of a memory location?

Dennis

I remember having read somewhere that in Pascal i value is not guaranteed after loop, although I have never found a Pascal compiler where in.
Nevertheless, you should never rely on i value after loop. It is a bad practice.

A little off topic, maybe you should think of using a while.

n:=1;
While (n<=100) and (IntArray[n] <= 100)
     do inc(n);

When the final round count is not the result of a complex computation, (like this case, 100), it is as fast as for loop and, IMHO, clearer.

of a memory location?

The for-loop-variable contains a valid value after the loop if the loop was left using a break or goto (this does not seem to be documented in FPC's language reference guide, but AFAIK it is in Delphi; also don't know what the ISO standard says about this...).

Regards,
Sven

I am not sure that this is intentional.
In fact I seem to remember mails from Jonas to the contrary, but he would need to confirm/deny that. As far as I know, the for loop variable is supposed to be undefined after the loop.

Michael.

Michael Van Canneyt wrote on Mon, 05 Oct 2015:

Yes, except if you use break/goto. Sven is correct and it's indeed the same in TP and Delphi.

Jonas

In that case I will add this to the docs.

Michael.

Sven Barth wrote

The for-loop-variable contains a valid value after the loop if the loop was left using a break or goto (this does not seem to be documented in FPC's language reference guide, but AFAIK it is in Delphi; also don't know what the ISO standard says about this...).

ISO/IEC 7185 :1990(E) says in section 6.8 .3.9 For-statements

After a for-statement is executed, other than being left by a goto-statement, the control-variable shall be undefined .

Regards,

Adriaan van Os

Thanks so much for clarification.

Dennis

"Adriaan van Os" wrote

Sven Barth wrote: > The for-loop-variable contains a valid value after the loop if the loop

was left using a break or goto (this does not seem to be documented in FPC's language reference guide, but AFAIK it is in Delphi; also don't know what the ISO standard says about this...).

goto-statement, the control-variable shall be undefined .

Thanks, so this applies to ISO as well ^^

Regards,
Sven

Delphi 7 follows ISO rule.

The loop:
for i := 1 to 100 do begin
   if IntArray[i] > 100 then  begin
    n := i;
    break;
   end;
end;
writeln('The '+IntToStr(i)+' item in the array > 100');
Doesn't produce a warning.
The loop:
 n:=-1;
 for i := 1 to 100 do begin
    if (IntArray[i] > 100) and (n<0) then
      n := i;
  end;
  writeln('The '+IntToStr(i)+' item in the array > 100');

Does: [Warning] FOR-Loop variable 'i' may be undefined after loop

thanks,
Dmitry

As written in this thread already it's guaranteed if and only if the loop had been left by break/goto.

Regards,
Sven