on goto
in [General Programming]
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From: Leif Roar Moldskred on 3 May 2010 10:50 In comp.programming Richard Heathfield <rjh(a)see.sig.invalid> wrote: > > Then how on earth do you /find/ anything? It's O(N^3), for pity's sake! No, it isn't. It's O( N ). (Hint: What's N the count of?) -- Leif Roar Moldskred
From: Nick Keighley on 3 May 2010 11:27 On 2 May, 14:37, spinoza1111 <spinoza1...(a)yahoo.com> wrote: > Juha, this guy is afraid to make a positive response, because he > bullies people who make "mistakes" and he's afraid of eating his own > dog food. this is a misuse of the term. You probably mean "take his own medicine"
From: gwowen on 4 May 2010 05:00 On May 2, 11:42 pm, James Kanze <james.ka...(a)gmail.com> wrote: > The only thing that's been conclusively proven is that the > SESE idiom never makes the code more difficult to understand. That is not a true statement.
From: Nathan on 6 May 2010 01:36 On Apr 28, 1:16 am, Juha Nieminen <nos...(a)thanks.invalid> wrote: > In comp.lang.c++ Richard Heathfield <r...(a)see.sig.invalid> wrote: > > > Juha Nieminen wrote: > >> In comp.lang.c++ Richard Heathfield <r...(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; > > } Hi Juha, I think that you either copied this from a poorly-written beginner C++ book or you failed to understand what the author was attempting to demonstrate with that kind of code and that you did not 'catch on' that it is not (in any way) demonstrative of how one walks a series of sequential cells in the real world. Why do you insist on writing control structures that serve little actual purpose? For instance, it should be obvious that you only require ONE loop and a few conditionals to achieve your desired (or assumed) goal. E.G... ,--- result = value xInd = 0 yInd = 0 zInd = 0 while ( data[xInd][yInd][zInd] != value && result != 0) { ++zInd; if (( zInd < data[xInd][yInd].size() ) != true ) { zInd = 0; + +yInd}; if (( yInd < data[xInd].size() ) != true ) { yInd = 0; ++xInd}; if (( xInd < data.size() ) != true ) { result = 0 }; } return result `--- Of course, this is a rather useless (maybe even retarded) function to begin with, because it only tells you IF the 'value' is located "somewhere" within that array -- it gives you absolutely no indication of "where" in that array you might be able to access the item which matches your search criteria. Please pardon any butchering of C++ syntax in my pseudo snippet above -- I totally lack any C++ training. But we alt.lang.asm folk *do* have an inkling of how to actually code our way out of a paper bag... I do believe. Nathan.
From: tonydee on 6 May 2010 02:11
On May 6, 2:36 pm, Nathan <nathancba...(a)gmail.com> wrote: > On Apr 28, 1:16 am, Juha Nieminen <nos...(a)thanks.invalid> wrote: > > 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; > > } > > Hi Juha, > > I think that you either copied this from a poorly-written beginner C++ > book or you failed to understand what the author was attempting to > demonstrate with that kind of code and that you did not 'catch on' > that it is not (in any way) demonstrative of how one walks a series of > sequential cells in the real world. > > Why do you insist on writing control structures that serve little > actual purpose? For instance, it should be obvious that you only > require ONE loop and a few conditionals to achieve your desired (or > assumed) goal. E.G... > > ,--- > result = value > xInd = 0 > yInd = 0 > zInd = 0 > while ( data[xInd][yInd][zInd] != value && result != 0) > { > ++zInd; > if (( zInd < data[xInd][yInd].size() ) != true ) { zInd = 0; + > +yInd}; > if (( yInd < data[xInd].size() ) != true ) { yInd = 0; ++xInd}; > if (( xInd < data.size() ) != true ) { result = 0 };} > > return result > `--- Juha did ask for something "simpler, cleaner and easier to follow", which your single loop is not. Perhaps because of that, your code needlessly compares yInd and xInd to their respective limits on every iteration, rather than something like... while ( data[xInd][yInd][zInd] != value && result != 0) { if {++zInd == data[xInd][yInd].size()) { zInd = 0; if (++yInd == data[xInd].size()) { yInd = 0; if (++xInd == data.size()) result = 0; } } ... More importantly, it can dereference index [0] before checking size(), so produces undefined behaviour. Anyway, IMHO it's far less clear (=self-evidently correct & efficient as well as maintainable) than Juha's code. > Of course, this is a rather useless (maybe even retarded) function to > begin with, because it only tells you IF the 'value' is located > "somewhere" within that array -- it gives you absolutely no indication > of "where" in that array you might be able to access the item which > matches your search criteria. You missed that the original function was returning a pointer to the matching cell, allowing a change to be made at that location, considerably more useful than the search-term-else-0-sentinel version you coded. > Please pardon any butchering of C++ syntax in my pseudo snippet above > -- I totally lack any C++ training. Fair enough... no worries. > But we alt.lang.asm folk *do* > have an inkling of how to actually code our way out of a paper bag... > I do believe. > > Nathan. Your central point that a single loop can serve contributes an interesting alternative, which I'm sure the readers here will appreciate, if they bother to look past your smug attitude (which is quite unwarranted given the serious errors in your implementation).... Cheers, Tony |