on goto
in [ASM]
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From: Richard Heathfield on 27 Apr 2010 14:45 Juha Nieminen wrote: > In comp.lang.c++ spinoza1111 <spinoza1111(a)yahoo.com> wrote: >> On Apr 25, 1:09 pm, Juha Nieminen <nos...(a)thanks.invalid> wrote: >>> In comp.lang.c++ Ali Karaali <ali...(a)gmail.com> wrote: >>> >>>> I use goto to break nested for loops and I can't see a >>>> reason to ban goto. >>> No. The correct keyword for breaking out of nested loops (in C++) is >>> 'return'. If you are using 'goto' for that purpose, you are doing it >>> wrong. >> Don't you mean "break"? > > Exactly how do you exit out of a set of nested loops with a "break"? I don't. I exit out of a set of nested loops using the conditions in the loop controllers. -- Richard Heathfield <http://www.cpax.org.uk> Email: -http://www. +rjh@ "Usenet is a strange place" - dmr 29 July 1999 Sig line vacant - apply within
From: Juha Nieminen on 27 Apr 2010 14:51 In comp.lang.c++ Richard Heathfield <rjh(a)see.sig.invalid> wrote: >> Exactly how do you exit out of a set of nested loops with a "break"? > > I don't. I exit out of a set of nested loops using the conditions in the > loop controllers. The idea was to make the code simpler, cleaner and easier to follow, not more complicated and contrived.
From: Richard Heathfield on 27 Apr 2010 15:01 Juha Nieminen wrote: > In comp.lang.c++ Richard Heathfield <rjh(a)see.sig.invalid> wrote: >>> Exactly how do you exit out of a set of nested loops with a "break"? >> I don't. I exit out of a set of nested loops using the conditions in the >> loop controllers. > > The idea was to make the code simpler, cleaner and easier to follow, not > more complicated and contrived. Yes. That's precisely why I use the conditions in the loop controllers. -- Richard Heathfield <http://www.cpax.org.uk> Email: -http://www. +rjh@ "Usenet is a strange place" - dmr 29 July 1999 Sig line vacant - apply within
From: Juha Nieminen on 28 Apr 2010 01:16 In comp.lang.c++ Richard Heathfield <rjh(a)see.sig.invalid> wrote: > Juha Nieminen wrote: >> In comp.lang.c++ Richard Heathfield <rjh(a)see.sig.invalid> wrote: >>>> Exactly how do you exit out of a set of nested loops with a "break"? >>> I don't. I exit out of a set of nested loops using the conditions in the >>> loop controllers. >> >> The idea was to make the code simpler, cleaner and easier to follow, not >> more complicated and contrived. > > Yes. That's precisely why I use the conditions in the loop controllers. Care to show an actual example of your "simpler, cleaner and easier to follow" version of exiting a nested loop by meddling with the loop conditions instead of using 'return'? For example, modify the following code to conform to your specifications: Value_t* MyClass::findValue(const Value_t& value) { for(size_t xInd = 0; xInd < data.size(); ++xInd) for(size_t yInd = 0; yInd < data[xInd].size(); ++yInd) for(size_t zInd = 0; zInd < data[xInd][yInd].size(); ++zInd) { if(data[xInd][yInd][zInd] == value) return &data[xInd][yInd][zInd]; } return 0; }
From: tonydee on 28 Apr 2010 03:12
On Apr 25, 7:47 am, James Kanze <james.ka...(a)gmail.com> wrote: > [...] in C and in > C++, for all "good" uses of goto (and a number of bad ones), the > language has specialized structures which better express the > meaning. Just not so. Much low-level state-based code is best expressed via gotos. There are a couple hundred usages spread over 7 different Boost libraries (as of 1.41). Have a look and you might find something you think reasonable. Sometimes working too much in a particular set of problem domains can either make it seem like goto isn't beneficial, or make it completely obvious it is. Parsers are one area where the uses are clear, for example: the boost regex parser. Similarly, some lexers I've written have employed gotos too... it's just cleaner. I'm pretty sure Walter Bright chipped in on an argument like this a couple years back, also supporting some uses of gotos... not somebody who's experience I'd challenge - will try to dig up the reference if anyone cares.... Cheers, Tony |