In <c6angc$cg3$1@oravannahka.helsinki.fi> Joona I Palaste <palaste@cc.helsinki.fi> writes:
[color=blue]
>Jerald Fijerald <jfj@freemail.gr> scribbled the following:[color=green]
>> Hi all.[/color]
>[color=green]
>> I was wondering if this expression is ok and has not any undefined
>> behaviors (bad style is not an issue):[/color]
>[color=green]
>> int x;
>> x = a [i] > 0 ? a [i++] : 1000;[/color]
>[color=green]
>> I believe it is ok because in the case[/color]
>[color=green]
>> x ? i++ : 0;[/color]
>[color=green]
>> 'i' is not incremented if x==0.
>> So it is ok, yes?[/color]
>
>This is completely OK, safe, kosher and hunky-dory. The ?: operator
>constitutes a sequence point, so a[i]>0 is guaranteed to have fully
>evaluated before either a[i++] or 1000 can begin evaluating.[/color]
More precisely, there is a sequence point after the evaluation of the
condition of the ?: operator, so this statement is the equivalent of
if (a[i] > 0) x = a[i++];
else x = 1000;
in the abstract C machine.
Dan
--
Dan Pop
DESY Zeuthen, RZ group
Email:
Dan.Pop@ifh.de 
