Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Eric Sosman Newsgroups: comp.lang.java.programmer Subject: Re: execution speed when printing Date: Tue, 14 Feb 2017 09:45:58 -0500 Organization: A noiseless patient Spider Lines: 43 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Tue, 14 Feb 2017 14:44:10 -0000 (UTC) Injection-Info: mx02.eternal-september.org; posting-host="616563f02882f59e8a2ff843b4737c27"; logging-data="7867"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19Aq0SpFOIWDHXUgZRKreK3" User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 In-Reply-To: Cancel-Lock: sha1:+E7gBP2VHz1B1wNq7r+54ZVC4N4= Xref: csiph.com comp.lang.java.programmer:36259 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" ); It might be faster. It might be slower. It might be faster sometimes and slower at other times. Here's something that stands a chance of being not only more user-friendly than either of the above, but perhaps faster, too: System.out.printf("%.1f miles%n", d); (Argument: Whatever you expend in mucking about with a variadic argument list, interpreting the format string, and assembling the output may be far less than it would cost to print a dozen or so utterly meaningless fraction digits.) > . 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.) If you don't have the time to write a microbenchmark studying a question that interests you, is it reasonable to expect other people to spend their time studying a matter of no interest to them? > If it is faster, should it be mentioned in a course for > beginners? No. Whatever you may think of my other opinions, I beg you to pay attention to this one: No. -- esosman@comcast-dot-net.invalid One thousand four hundred thirty-six days to go.