I want to thank all respondents for the list of books and websites. It will
take me a few days to go through each email and recommendation.
To others who were concerned about the use of memset(), I do use memset, when
there are no linked lists. My structures that I zap rarely if ever contain
pointers to linked lists. Typically in my code I do a xx=alloc(sizeof struct
yyy) followed by a memset, or I do xx = calloc(sizeof struct yyy) because I
want hex zeros everywhere when the xx is initialized.
I tend to keep integers or short strings or string pointers when allocating a
new structure. The null pointer is what I do want when there is a new
allocation.
I have too many years of assembly, Pascal and C, so that I am after easing the
transition to thinking and working with objects, mainly in a gui environment .
For example in C, we tend to use individual #include files. whereas in CPP,
because of classes I noted that the tendency is to do #include within
#include's, due to class definitions. I think that in general #includes within
#includes is wrong.
I should bring this question up on a programming website, but posted it here to
explain what irks me and blocks me from accepting OO.
I am practicing with QT and the SDK.
------------------
Regards
Leslie
Mr. Leslie Satenstein
50 years in IT and going strong.
Yesterday was a good day, today is a better day,
and tomorrow will be even better.
mailto:[email protected]
alternative: [email protected]
www.itbms.biz
>________________________________
> From: Andy Pintar <[email protected]>
>To: Montreal Linux Users Group <[email protected]>
>Sent: Tuesday, March 20, 2012 10:56 PM
>Subject: Re: [MLUG] Off Topic C++ course
>
>On Tue, 20 Mar 2012, Patricia Campbell wrote:
>
>> >From your email you are thinking in non OOP terms. If you want to use C++
>> you will have to switch your thinking a bit. I recommend Deitel & Deitel
>> C++ any version > 5 will probably do for
>> conceptshttp://www.amazon.com/How-Program-8th-Paul-Deitel/dp/0132662361
>
>Great advice as always, Patricia. I'd recommend Bruce Eckel's "Thinking in
>C++" first and second volumes.
>http://mindview.net/Books/TICPP/ThinkingInCPP2e.html
>
>They're free, easy to read/follow, plenty of bite-sized examples, and I think
>much more intuitively organized than, say, the O'Reilly nutshell/programming
>books.
>
>> If I can do sizeof(structure) to get its size in memory. Can I do the
>> same of a class. sizeof(class) ?
>
>Structs and classes are the same, the only difference is public vs private by
>default. But structs in C++ aren't the same as structs in C! Read a
>thorough, detailed intro book and you'll see why thinking of C++ as an
>extension to C is a bad idea. It is probably one of the greatest disservices
>to C programmers who want to learn C++, who think 'oh it's just some language
>extensions.' But sizeof works as expected.
>
>> One other question. In C, I can do a memset(structure
>address, 0, > sizeof(structure)), and that will zap the structure.
>
>Don't do that! Even in C! Sure, for a struct that contains a pair of floats
>that's fine (some kind of point(x,y) struct). But what about a linked list
>implementation? If you have a linked list that cointains a {pointer to value,
>pointer to next item}, and you zap the head of your list, you didn't clean up
>the value or the other elements, just 2 pointers. What, you had thousands of
>items in that list? And no way to accesss them? Memory leak! Same holds
>true in c++, that's why you have a destructor that you write which goes
>through each element explicitly.
>
>But more importantly, why are you memsetting it to zero (in C)? That makes no
>sense at all.. sure you could do it, but why not just set the struct's
>elements to zero? Or if you want to 'delete' it, just let it fall out of
>scope... Please share the point of that 'zap' and I or someone else can
>better explain an equivalent idea in C++.
>
>> Can I put the structure within a class and do the same? I think I am
>> not able to do the memset(?class,0 sizeof(class))
>> clearout because of private variables.
>
>Structs=classes. Sort of. But don't go memsetting like that. You're going
>to end up with really broken code really quickly. If you think you're going
>to save some cycles, you're wrong. Create a method, say 'clear()', that sets
>internal class/struct state to "zero", or somesuch.
>
>
>Check out Eckel's books. Don't go into it thinking you can use any of your C
>knowledge (other than where to put a ';' or scope blocks inside '{' '}',
>etc). It's a totally different approach that's designed to make it easier to
>represent abstract concepts more efficiently than in procedural C. That
>doesn't mean the code is faster, although it often is for complex projects
>because it is more concisely defined than it could be in C.
>
>Blah blah blah....
>Sorry for the long post, I hope you find it helpful.
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>
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