Variable scope: inside or outside the loop

Per Bothner per@bothner.com
Mon Aug 30 17:32:00 GMT 2004


Reshat Sabiq wrote:

> Stylistically i like and usually declare variables inside the loop, when
> they are not used outside the loop, and no avoidable malloc overhead is
> caused.
> However, if the compiler is not smart enough to push and pop only once,
> outside the loop, in this case each iteration of the loop will run with
> the unnecessary overhead of push and pop.

Declarations do not cause pushes/pops.  Moving a declaration (as opposed
to the initialization) does not change the generated bytecode.  (It may
change the debugging info.)

> P.S. Does the answer change from Java, to C++, to VC++?

No.

> P.P.S. If there is no definitive answer, should the second approach be
> used just out of caution?

No - use the first approach.
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/



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