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From: =?UTF-8?Q?Arne_Vajh=c3=b8j?= <arne@vajhoej.dk>
Newsgroups: comp.lang.java.programmer
Subject: Re: execution speed when printing
Date: Mon, 13 Feb 2017 20:32:16 -0500
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On 2/13/2017 7:48 PM, Stefan Ram wrote:
>   I believe that (assuming »d« has type »double«)
>
> java.lang.System.out.print( d );
> java.lang.System.out.println( " miles" );
>
>   might be faster than
>
> java.lang.System.out.println( d +" miles" );
>
>   . Do you think that on most implementations it will really
>   be faster? (Yes, I know. But would I write a post, if I had
>   time to write a microbenchmark? Moreover, a part of the cost
>   of the »+« might escape a microbenchmark, when it occurs in
>   a GC run that happens only much later but might increase the
>   overall runtime of a program.)
>
>   Ok, printing to a console always is very slow, but the
>   output might be redirected to a file, and it might serve
>   as a model for similar situations that do not involve I/O.
>
>   If it is faster, should it be mentioned in a course for
>   beginners?

I think it would be a disaster to get beginners focused on
that sort of premature optimization.

Regarding the issue itself then it is not obvious to me that the
concatenation is more expensive than the extra calls.

Arne