Партнёры:
Хостинг:
Archive-name: C-faq/learn
Posting-Frequency: monthly
Last-modified: 23 August 1999
URL: http://www.raos.demon.co.uk/acllc-c++/faq.html
This document is a FAQ list for the newsgroup alt.comp.lang.learn.c-c++.
It provides readers with a framework and a set of guidelines for posting
here, in addition to answering a number of questions newcomers here tend
to ask.
This FAQ is meant to be read in its entirety. It is posted monthly to
alt.comp.lang.learn.c-c++, comp.lang.c, comp.lang.c++,
comp.lang.c.moderated, comp.answers, alt.answers and news.answers.
This is the plaintext version of this list. An HTML version can be
located at
http://www.raos.demon.co.uk/acllc-c++/faq.html
Compiled by Sunil Rao <[email protected]>.
Comments, suggestions, corrections, constructive criticism and requests
for clarification will be gratefully acknowledged.
Last update: 23 August 1999
Last changes made: Updated and expanded the answers to questions 6,
10, 15, 16, 17, 18 and 19.
To do list: To add answers to a number of questions and to update
information regarding compilers.
Special Thanks to...
Dennis Swanson, Jim Gewin, Billy Chambless, Mark Brown, Dave Dunfield,
Jack Klein, Steve Summit, Steve Clamage, Dennis Ritchie, Kaz Kylheku,
Lars Hecking, Pablo Halpern, Jerry Coffin, Stuart Hall, Dann Corbit,
Michael McGoldrick, Cameron Foster, Brody Hurst, Jabari Adisa,
Wieland StЭbinger, Chris Newton and Bernd Luevelsmeyer
for their helpful comments, suggestions, advice, corrections and
constructive criticism, and (in the case of some) for permitting me to
quote from their papers/posts.
1: What is the purpose of this newsgroup?
alt.comp.lang.learn.c-c++ is an unmoderated newsgroup for the
discussion of issues that concern novice and non-expert programmers
in C and C++ who wish to *LEARN* more about one or both of these
languages.
That probably looks scary. Basically, anybody can post to the
group. Provided the questions you post are on-topic and the answers
you provide are accurate, you should not have a problem. If your
question is off-topic, you will typically be redirected to a
newsgroup that is more appropriate; if your answers are
inaccurate, you risk being corrected with a flame.
2: What is C/C++?
First of all, C and C++ are different languages. C was created by
Dennis Ritchie as an efficient language for systems programming.
Bjarne Stroustrup then extended C by adding features to support
object-oriented programming. C++ can be considered to be a
superset of C, but there are real differences between them.
It can usually (though not always) be assumed that anybody who
talks about "C/C++" as one language is no expert - this extends
to book authors too. It is normally unclear whether somebody is
referring to "C OR C++" or "C AND C++" when using this expression,
so it is probably best avoided.
3: So, are C and C++ not so similar after all?
They are indeed similar to a great extent. Incompatibilities do
exist, though, and many idiomatic constructs used in C are frowned
upon by C++ experts. C++ programmers generally consider code that
does not exploit those features of C++ that make it possible to
write better programs - programs that are more readable and easier
to write and maintain - to be in poor style. The differences
between the two languages are significant enough to ensure that
one has to be clear about the language being used. However, it
must not be forgotten that C++ is a largely a superset of C, and
that it is possible (though perhaps not desirable) to write code
that works correctly in both languages.
A lot of people incorrectly believe that object-oriented
programs cannot be written in C; this is not true. What is true
is that C++ provides features that make it easier to write in a
style that is object-oriented; in other words, C++ supports
programming in an object-oriented style.
4: What is the difference between this newsgroup and comp.lang.c or
comp.lang.c++?
This newsgroup is primarily intended for discussion related to the
LEARNING of C and C++. The other two groups are primarily intended
for discussion of the features of the respective languages
themselves. Naturally, some overlap does occur. This group does tend
to be slightly (perhaps excessively so) more informal, though. Most
regulars on this group show great patience with many common
beginners' questions and will willingly expound on many topics of
interest or particular difficulty, referring to appropriate
reference material, either in printed or in electronic form, as
necessary.
5: What kind of questions may be asked here?
Any question relating to any aspect of C or C++ that you're having
trouble understanding is on topic here. By C, what is meant is the
language PROPER and its standard library as defined by ANSI and ISO.
C++ discussions are about the proposed language standard (that
recently passed its formal vote) and the library it defines. Any
questions relating to specific compilers, third-party or non-
standard libraries, compiler extensions etc are unwelcome here, and
will probably be answered with a redirection to a more appropriate
newsgroup.
If you've been thus redirected, do not get miffed or upset and post
an angry response - it will cut no ice with the regulars and will
only label you as an unwilling learner. What's discussed in this
group is rigidly defined to limit the traffic and make the group
useful to as wide a possible audience as possible.
6: I have a burning question about XXX. What should I do first?
First of all, do check to see if your question has not been been
answered before. Look up any of the standard references on the
language. If you can't find the answer, browse the group, lurk here
for a few days, search the archives at Deja.com, read the relevant
FAQs (including those of comp.lang.c and comp.lang.c++), and if you
STILL can't find the answer, post by all means.
Note that you might not be the first ever learner to have run into
your problems. There is a good chance that your question has been
answered before.
Deja.com: http://www.deja.com/
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
C++ FAQ: http://www.cerfnet.com/~mpcline/c++-faq-lite/
7: What other points should I make note of BEFORE posting here?
Please observe basic Netiquette guidelines. If you're not sure of
what these are, subscribe to news.announce.newusers, and read *ALL*
of the posts there. A good reference is
http://www.ezine.com/netiquette.html
To summarise these points very briefly - ensure that your post is
on topic. Do your homework before posting. Don't post the same
question one hundred times. Don't troll. Don't post homework
questions without anything to show your effort. Don't ask for
replies to be sent by email. Don't post binaries. Make sure that
your subject line is an accurate description of the problem/topic.
Please do not ask for replies by email. If you haven't got the time
or patience to read the newsgroup, that's tough. The answers you
receive might benefit other readers of the newsgroup as well, and
you yourself might learn more from the discussions your question
might generate.
If you have to reply, be accurate and precise - your reply is being
read by LEARNERS, remember. If you are unsure or have nothing new
to add, don't bother.
For heaven's sake, don't get abusive when you are corrected or
redirected. If you are unsure as to why you have been redirected,
ask the person who did so *PRIVATELY* by email. There usually is
a good reason - see question 9.
Do not take any answers on trust. Sadly, many of those who post
answers here know even less than the interested learner who posted
the original question. Wait for a few days before relying on any
posted code or answers, just in case they might be corrected by
others. This is also why it is a very bad idea to email your
questions directly to regulars; you have no insurance against
any potential mistakes - remember that nobody is infallible.
Please do not make any MIME or UUENCODED posts (this includes
HTML). Many newsreaders cannot handle such posts correctly. You
will only make it impossible for many to read your posts.
And please try not to flame. This is a learners' group. Not
everyone who posts here is aware of all the issues involved. A
grumpy attitude only makes things difficult for everyone
concerned.
It usually helps if you indicate in somewhere in your post if
you're expecting a C or a C++ answer - several techniques
appropriate to C++ will not work in C, and some C programs will
not work or are considered bad style under C++. It also makes it
easier for other readers - they can then safely ignore your post
if they cannot help you with it. If you're not sure as to which
language you're learning, you probably need to get better
resources to learn from.
8: I posted a homework question, but got no help; only sarcastic
responses. Why?
Homework questions are in general not welcome here - most attempts
to disguise one usually do not work particularly well. You will
typically receive no help unless you can demonstrate that you have
made an honest attempt to solve the problem yourself, by posting
some code you have trouble with, for instance.
There is little point in a regular supplying you with code to
fulfil an assignment if you are going to pass the course and come
out and work on real-world projects without knowing how to even
tackle a basic homework problem. See also
http://home.att.net/~jackklein/ctips01.html#homework
http://members.xoom.com/jshiva/hw.txt
9: Why are questions relating to Windows, Graphics, Sockets etc. off-
topic here?
Questions on these topics come up every so often here. C and C++
are languages, not operating systems. They come with limited,
though highly useful, standard libraries. While any question
relating to these libraries is relevant and most certainly on
topic, a question relating to MFCs, for instance, is of absolutely
no interest to a Unix expert, and vice-versa. There exist
newsgroups DEVOTED to these non-standard additions. It certainly
makes more sense to post a question in a place where there is a
greater chance of it being answered, and answered correctly. As
a beginner, it probably makes more sense to concentrate on the
core language itself and master that before branching off to
learn system-specific tricks.
See also http://members.xoom.com/jshiva/offtopic.txt
10: What are some other related groups where I might post questions?
(Answer adapted from the regular "Welcome to comp.lang.c" post
by Billy Chambless and Tim Behrendsen)
You *really* ought to be able to work out where to post by
yourself. Please, please, please, for heavens' sake read the
FAQs and lurk for a while before posting your questions.
Please do not post to more groups than are necessary. Think
carefully about the relevance of your post before you post to any
of the newsgroups mentioned below. If you decide that your question
is indeed relevant to more than one newsgroup and is not a FAQ,
please cross-post rather than multi-post. Remember that many
regular readers of this newsgroup also follow several of the other
groups mentioned below.
Note: if your news server does not carry the borland, microsoft or
watcom newsgroups, you might find it necessary to connect
to forums.borland.com, msnews.microsoft.com or forums.sybase.com
instead. See also
http://www.borland.com/newsgroups/
http://sdn.sybase.com/sdn/appdev/newsgroups.stm
* Language Issues
C comp.lang.c, comp.lang.c.moderated
C++ comp.lang.c++.moderated, comp.lang.c++
x86 assembly comp.lang.asm.x86
* Non-language-specific Issues
Algorithms comp.programming
Graphics comp.graphics.algorithms
Another avenue worth exploring for general algorithms questions
might be the bulletin board at the Analysis of Algorithms
homepage based at http://pauillac.inria.fr/algo/AofA/ and
mirrored at http://www.cecm.sfu.ca/mirror/INRIA/algo/AofA/.
There is a real difference between an algorithm and an
implementation thereof. A question regarding an algorithm itself
is, strictly speaking, off-topic though issues do get raised here
in the absence of any good newsgroup to discuss them in.
Questions relating to implementations are of course on-topic
here.
* Compilers/Libraries
The gcc compiler gnu.gcc
DJGPP (gcc for DOS) comp.os.msdos.djgpp
Borland C++ borland.public.cpp
borland.public.cpp.language
Borland C++Builder borland.public.cppbuilder
borland.public.cppbuilder.language
Visual C++ microsoft.public.vc.ide_general
microsoft.public.vc.language
Watcom C/C++ powersoft.public.watcom_c_c++.general
CodeWarrior comp.sys.mac.programmer.codewarrior
MFC microsoft.public.vc.mfc
comp.os.ms-windows.programmer.tools.mfc
OWL borland.public.cpp.owl
comp.os.ms-windows.programmer.tools.owl
VCL borland.public.cppbuilder.vcl
* Operating Systems/System Specifics
DOS issues comp.os.msdos.programmer
MS Windows comp.os.ms-windows.programmer.misc
microsoft.public.win16.programmer.*
microsoft.public.win32.programmer.*
OS/2 comp.os.os2.programmer.misc
Macintosh comp.sys.mac.programmer.misc
General UNIX comp.unix.programmer
Amiga comp.sys.amiga.programmer
11: HELP! My program does not work correctly. What do I do now?
Before posting code here, try and make sure that it at least
compiles correctly, even if it does not quite behave the way you
intended it to. Try and localise your error to a particular
function or section of code - most readers have no time to wade
through pages of code (If you are unable to do this, you probably
need to start again from scratch anyway.). Do NOT under any
circumstances post all of your code as an attachment - many will
simply ignore your post. Please also specify if your code is C
or C++.
Essentially, post the smallest complete program that manifests the
problem. This makes it easier for the reader to answer your
question. You might find that doing this enables you to answer
your question yourself!
Read the answer to the above question as well. And do learn how to
use the debugger that came with your compiler. It usually helps if
you set the warning levels to the highest possible for your
compiler - let the compiler pick out any errors and warn you of
any potential problems. And if you post any errors or warning
messages with your code, it makes it that much easier for a
regular to see what's wrong with your code - any need to compile
it yet again will be minimised, especially if the error is a
common one.
12: What online tutorials exist for learning C and C++?
The best online tutorial for C I have come across has got to be
Steve Summit's class notes for the C courses he teaches.
http://www.eskimo.com/~scs/cclass/cclass.html
There are references to other C tutorials in his C FAQ as well.
Vinit Carpenter maintains a list of resources for learning C
and C++. Do note, however, that a fair number of the tutorials
placed online contain mistakes and/or are out of date.
http://www.cyberdiem.com/vin/learn.html
Ted Jensen's tutorial on pointers and arrays in C can be found
at http://pweb.netcom.com/~tjensen/ptr/cpoint.htm
Tom Torfs has written an excellent, complete tutorial, meant
to complement a good introduction to C. It's not primarily
intended for the complete beginner to the language, though.
http://members.xoom.com/tomtorfs/cintro.html
See also the answer to question 18.
13: What should I look for when picking a book to learn from?
Opinions vary widely. Most readers recommend the book(s) they
learnt from, regardless of whether or not they might actually be
suitable for the learner. The fact that many commonly recommended
books are either full of errors or hopelessly out of date (or
even both!) makes matters worse.
Beware of books that claim to teach you both C and C++ - they might
end up teaching you a horrible hybrid instead. It is also probably
better to stick to books that conform to the C and C++ standards,
at least while beginning. Many compiler-specific books do not go
into sufficient depth regarding important language issues and
usually fail to be clear as to whether something is specific to the
compiler under consideration or not.
Some texts come bundled with compilers - it's usually worth
checking to see how out-of-date the compiler actually is. For C,
this is probably less of an issue than it is for C++, simply
because compiler writers have had over a decade to catch up with
the standard.
It pays to keep more than one good book handy; many books known for
their technical accuracy can seem dense and unreadable in places,
and you might at times need to back up a primer with a reference.
Do make sure that you get the latest edition of any of these books
you decide to purchase. Also please check to see if there is an
errata list available online for any book you decide on; this is
particularly important for programming language texts. It pays to
be suspicious of books for which such lists cannot be located
online for whatever reason.
The Association of C and C++ Users maintains a collection of book
reviews taken from its journals. Many of the reviews are fair and
excellent in their criticism, though there are a few minor
inconsistencies and a number of truly awful books have escaped
with favourable reviews. It's a useful starting-point, though.
http://www.accu.org/bookreviews/public/
Many C and C++ experts recommend against using ANY book written by
a certain Herbert Schildt. To see why, read the answer to question
16. The "Dummies" series of books is not particularly
well-regarded either in general.
14: What are the best books I can learn C from?
If you wish to learn C, the classic text - the "Bible" - is "The C
Programming Language", 2nd Edition, by Brian Kernighan and Dennis
Ritchie. This hallowed text describes and explains ANSI C. K&R2 is
renowned for its brevity, clarity, elegance and completeness; but
these very factors can make it heavy going for the beginner.
http://cm.bell-labs.com/cm/cs/cbook/
K N King's "C Programming: A Modern Approach" is another text
frequently recommended on comp.lang.c. This book is a good,
thorough introduction to C that is a lot easier to work with
from a beginner's perspective.
http://knking.com/books/c/
Another frequently recommended book on C is "C - How to
Program", 2nd Edition, by H M Deitel and P J Deitel. Please note
that I have not had a chance to read this book, and include the
reference on the strength of the the recommendation of a number
of regular posters to comp.lang.c.
http://www.deitel.com/products_and_services/publications/chtp2.htm
15: What are the best books I can learn C++ from?
Before going further, I should mention that I am not a C++
programmer myself, and the recommendations listed here are based on
positive comments I have heard from others.
The C++ equivalent of K&R2 is "The C++ Programming Language", 3rd
Edition, by Bjarne Stroustrup. Experienced C++ programmers love it;
however, many beginners seem to find it very hard going indeed.
Like K&R2, it assumes basic familiarity with programming concepts
and is not really intended for the absolute beginner. It does not
assume any previous knowledge of C.
http://www.research.att.com/~bs/about_3rd.html
A more accessible book that is intended for beginners is "C++
Primer", 3rd Edition, by Stanley Lippman and JosИe Lajoie. This
book is thorough, and conforms to the C++ standard. It is
reportedly extremely clear and detailed, and, again, does not
assume any previous knowledge of C.
http://cseng.aw.com/bookdetail.qry?ISBN=0-201-82470-1&ptype=0
Another text I've seen seen particularly recommended is "C++ - How
to Program", 2nd Edition, by H M Deitel and P J Deitel. Again, this
text does not assume prior knowledge of C.
http://www.deitel.com/products_and_services/publications
/cpphtp2.htm
Other texts I have seen recommended a number of times on the C++
newsgroups include the badly-named-though-often-recommended "Teach
Yourself C++ in 21 days" by Jesse Liberty, "C++ Primer Plus" by
Stephen Prata, and "Thinking in C++" by Bruce Eckel.
http://www.libertyassociates.com/book_edit.htm#21 Days
http://www.bruceeckel.com/books.html#ThinkingInCPlusPlus
Bruce Eckel has also placed a "beta" of the second edition of his
"Thinking in C++" online as well. Do remember that it isn't the
final version and that there might remain some as-yet undetected
errors.
http://www.eckelobjects.com/ThinkingInCPP2e.html
The C++ FAQ contains some recommendations for C++ books as well.
16: Why do many experts not think very highly of Herbert Schildt's
books?
A good answer to this question could fill a book by itself. While
no book is perfect, Schildt's books, in the opinion of many
gurus, seem to positively aim to mislead learners and encourage
bad habits. Schildt's beautifully clear writing style only makes
things worse by causing many "satisfied" learners to recommend his
books to other learners.
Do take a look at the following scathing articles before deciding
to buy a Schildt text.
http://www.lysator.liu.se/c/schildt.html
http://herd.plethora.net/~seebs/c/c_tcr.html
The above reviews are admittedly based on two of Schildt's older
books. However, the language they describe has not changed in the
intervening period, and several books written at around the same
time remain highly regarded.
The following humorous post also illustrates the general feeling
towards Schildt and his books.
http://www.qnx.com/~glen/deadbeef/2764.html
There is exactly one and ONLY one C book bearing Schildt's name on
its cover that is at all recommended by many C experts - see Q 25.
17: Where can I get a free C or C++ compiler?
(Answer adapted from Joe Buck's FAQ for g++ and libg++.)
* gcc
gcc is a free C and C++ compiler from the Free Software
Foundation available for many Unix-based systems. Its ports for
other systems are also freely available.
http://www.fsf.org/software/gcc/gcc.html
ftp://prep.ai.mit.edu/pub/gnu/
egcs (the experimental gnu compiler system) is another free
project (based on gcc). Check out
http://www.cygnus.com/egcs/
The MS-DOS port (DJGPP) of gcc runs on a 386 or higher, and is a
full 32-bit compiler. Make sure you read the FAQ thoroughly
first, however, and post any questions you have regarding its
setup to comp.os.msdos.djgpp, not here.
http://www.delorie.com/djgpp/
For a port of gcc that works on 32-bit Windows, look at
http://www.cygnus.com/misc/gnu-win32/
Also, for another port, see
http://www.xraylith.wisc.edu/~khan/software/
gnu-win32/egcs-mingw32.html
You could also get hold of Bloodshed Dev-C++, which is
essentially Mingw32 bundled with an editor, packaged in an
easier-to-use form.
http://www.bloodshed.nu/devc.html
For the Amiga, BeOS, and pOS, look at the GG port of gcc at
http://www.ninemoons.com/GG/
EMX is a port of gcc to OS/2 that also works on DOS.
http://www.os2ss.com/unix/emx09c/
* lcc
lcc-win32 is a free C compiler available for 32-bit Windows.
http://www.cs.virginia.edu/~lcc-win32/
It is based on the retargettable lcc system.
http://www.cs.princeton.edu/software/lcc/
* Pacific C
The Pacific C compiler is available for free for personal use.
You can download it from
http://www.hitech.com.au/products/pacific.html
* MPW
If you're programming under the Apple Macintosh, you can obtain
the Macintosh Programmers' workshop for free.
http://developer.apple.com/tools/mpw-tools/
* Turbo C
Inprise (formerly known as Borland) have commenced making older
versions of their software available for free download. This
includes older (possibly pre-standard) versions of their Turbo C
compiler.
http://community.borland.com/museum/
* Micro-C
If you are looking for a free C compiler for MS-DOS that is easy
to install and use, take a look at Micro-C, available from
http://www.dunfield.com/
Do bear in mind that it is not wholly compatible with
the standard. The incompatibilites are well-documented, however.
18: What good websites/online references exist for C and C++?
http://www.lysator.liu.se/c/ is an excellent resource for C,
containing a number of extremely useful links and pointers.
For beginners to C (and C++), Jack Klein has put up an excellent
page with tips, suggestions and expanded answers to a number of
commonly asked beginners' questions.
http://home.att.net/~jackklein/c/c_main.html
The Comeau Computing web site features several highly informative
and useful resource pages, including
http://www.comeaucomputing.com/resources/litsuggs.html
http://www.comeaucomputing.com/faqs/cppfaq.html
Steve Summit has archived some of his longer and more informative
Usenet posts at
http://www.eskimo.com/~scs/readings/index2.html
Check out the C++ Virtual Library for some useful C++ links.
http://www.desy.de/user/projects/C++.html
You may wish to look at the C Language Online Journal at
http://www.cs.wustl.edu/~jxh/CLOJ/
For some useful code snippets (some portable; others not),
check out Bob Stout's SNIPPETS archive at
http://www.snippets.org/
Karim Ratib's well-indexed code page has links to many useful
resources.
http://www.iro.umontreal.ca/~ratib/code
Martin Leslie's C Programming reference site is at
http://www.gator.net/~garyg/C/c.html
Jamie Blustein's C Programming Language resources are at
http://www.csd.uwo.ca/~jamie/.Refs/C-refs.html
Scott McMahan's C Programmer's Notebook, which discusses a
number of issues C programmers encounter as their experience
grows, is at
http://www.skwc.com/essent/prognotebook.html
Some questions relating to what standard C is all about are
answered at
http://lglwww.epfl.ch/~wolf/c/
Also, check out
The Mining Company's C/C++ site,
http://cplus.miningco.com/
Jon Morris Smith's C++ resources directory,
http://www.cs.bham.ac.uk/~jdm/cpp.html
Robert Davies' list of online C++ references,
http://nz.com/webnz/robert/cpp_site.html
The #C++ site,
http://www.cl.ais.net/morph/c++/main.html
and Simo Salminen's Programmers' Oasis C and C++ page.
http://www.utu.fi/~sisasa/oasis/oasis-cc++.html
19: Should I learn C before learning C++?
According to a number of C++ experts, including its creator Bjarne
Stroustrup, and Marshall Cline (the author of the C++ FAQ), the
answer is a firm no.
Look up the C++ FAQ to see why Cline thinks you do not need to
learn C before C++. A post by Bjarne Stroustrup to comp.lang.c++
addresses this point too.
http://www.research.att.com/~bs/learn.html
"Learning Standard C++ as a New Language" - a paper by Stroustrup
available from http://www.research.att.com/~bs/papers.html -
examines this much-debated issue in great depth, but the paper is
aimed more at educators than at beginners.
20: What is the difference between C++ and Visual C++?
C++ is a programming language. Visual C++ is Microsoft's
implementation of it. When people talk about learning Visual C++,
it usually has more to do with learning how to use the programming
environment, and how to use the Microsoft Foundation Classes (MFCs)
for Windows rather than any language issues. Visual C++ can and
will compile straight C and C++.
21: What is portability? Why are so many people concerned about it?
C and C++ are languages that are not tied down to a particular
platform. This means that, with care, it is possible to write useful
code in either of these languages that will run on different
platforms without modification.
That is not to say that ALL code written in these languages must
conform strictly to the standards - in practice it is sometimes
neither possible nor desirable to achieve this aim. However, the job
of porting code is made easier when any system-specific stuff is
carefully packaged or abstracted away, so that it is clear and
straightforward to make the necessary changes during a port.
In order to be able to do this effectively, it is important to be
aware of what can and can not be done within the realms of the
standards set by these languages. That is why a lot of importance is
placed on adhering strictly to the standards, at least while
learning.
22: How do I BEGIN to write C or C++ under Visual or Borland C++?
This question is, strictly speaking, off-topic, but is answered
here since it's one that seems to plague many beginners.
To start with, you need to make sure that you are not writing a
Windows application. Try creating a new project or application
to target MS-DOS, QuickWin or Win32 Console depending on your
compiler version. You can then use the Standard C and C++
libraries to write strictly conforming programs. It's best to
learn to write standard-conforming programs first before
branching off into writing Windows programs.
If you find that you are having a lot of trouble setting up your
compiler, a good place to ask questions is a newsgroup devoted to
your compiler. See Question 10 for a list of such groups.
23: HELP! My program seems to compile correctly, but when it runs, a DOS
window flashes and then vanishes.
This can sometimes occur when you are developing programs using an
IDE. A command prompt window opens and displays the output, and
control is passed back immediately to the IDE.
To get around this, you can look through the various menus to find
a "View Output Screen" option. Alternatively, you could open a
command prompt window and change directory to the one your
executable is going to end up in and run your executable directly
from there.
The solution of using a non-standard function to keep the
executable running until a key is pressed is not a very good idea -
especially if you are going to run your program outside of the
development environment.
24: Why doesn't this FAQ cover language issues?
This is because other better, more comprehensive resources exist
for this purpose. See the answers to questions 12 and 18.
25: Where can I obtain a copy of the standards for C and C++?
You cannot obtain copies of the standards for free. This is because
the standards organisations earn a large part of their revenue from
selling printed copies.
The C FAQ tells you how you can obtain copies of the C standard.
You could also buy "The Annotated ANSI C Standard", by the
afore-mentioned Herbert Schildt (question 16). Make sure that you
ignore the annotations completely, however.
The C++ standard can be obtained online directly from the ANSI
Electronic Standards store . After registering yourself for free,
you can download the document in Adobe PDF format on payment of
$18.00 (US) by credit card.
http://webstore.ansi.org/ansidocstore/default.asp
The standards documents can be daunting at first sight; meant, as
they are, to be as formal and precise as possible. They are NOT
suitable for learning from, but are intended rather to be used as
the ultimate authority to check with on any language issue.
Also, check the comp.std.c++ FAQ.
http://reality.sgi.com/austern_mti/std-c++/faq.html
26: HELP! I get errors when I try to compile "hello, world"!
Check your source to make sure you haven't missed any semi-colons
or braces. Also remember that C and C++ are case-sensitive - Main()
and main() are completely different, for instance. If you are
satisfied that the program source is all right, then you probably
have not set your compiler up properly. You might need to ask one
of the experts in a newsgroup devoted to your compiler about this -
see the answer to question 10.
The sole reason for redirecting compiler setup questions to other
groups is to reinforce the point that a language is inherently
separate from an implementation of one. There are simply too
many different implementations of C and C++, and too many
subtleties involved in the actual learning of C and C++ for all
of them to come under the banner of this newsgroup.
27: Which language should I learn first then - C or C++?
The answer to this depends on your own inclinations. C is a
smaller, less complex language than C++, and is consequently easier
to master. However, it is probably easier to get up to speed with
C++, if you make effective use of the standard library. Some find C
to be more elegant than C++, others think it to be too "unsafe".
C++ programmers generally feel that it has features that make it
easier to write good, robust, readable and maintainable code in
than in C.
If you do decide to learn C++, there is little point in learning
C itself first. See also question 19.
If you have little or no programming experience, be prepared to
face a real challenge. C and C++ have enough quirks and subtleties
to catch out even expert programmers in other languages. It's not
impossible to learn to program with C or C++ as a first language,
just more difficult than with Turing, Pascal or a structured
BASIC, for instance. Programming in C or in C++ is generally
considered to be a more pleasureable experience than doing so
in beginners' languages by those experienced in either, but the
very fact that your freedom is limited and restricted by these
languages makes them easier to learn.
28: Why are C and C++ so popular and widely-used?
(First part of answer adapted from a March 1998 comp.lang.c post
by Kaz Kylheku on "Why Has C Proved To Be Such A Succesful
Language")
C has always been a language that never attempts to tie a
programmer down - it allows for easy implementation, it comes with
a genuinely useful standard library that can itself be implemented
in C, and it is both efficient and portable. C has always appealed
to systems programmers who like the terse, concise manner in which
powerful expressions can be coded. C was widely distributed with an
Operating System (Unix) that was actually largely written in C
itself. Also, C allowed programmers to (while sacrificing
portability) have direct access to many machine-level features that
would otherwise require the use of Assembly Language.
As Dennis Ritchie writes in his paper, "The Development of the C
Language",
C is quirky, flawed, and an enormous success. While accidents
of history surely helped, it evidently satisfied a need for a
system implementation language efficient enough to displace
assembly language, yet sufficiently abstract and fluent to
describe algorithms and interactions in a wide variety of
environments.
C++ has its basis in C - extending it by supporting features meant
to encourage and support the development of large programs. Perhaps
most importantly, it supports object-oriented programming in a
familiar setting and framework (that of C). When C++ was created,
one of the initial aims was to retain compatibility with C to as
large an extent as possible, and retain its spirit and efficiency.
It was possible to convert from C to C++ gradually, thus making use
of C++ (initally, at least) as a "better C", and moving on to
using other features. This allowed many C programmers to learn C++
quickly (though using C++ effectively requires a major mind-shift
for many C programmers).
29: Why is this FAQ so grumpy/terse/curt/unfriendly?
A lot of questions posted in alt.comp.lang.learn.c-c++ are posted
by people who are generally unsure about what they are learning.
Many beginners fail to appreciate that C and C++ are used on a
number of platforms, and that what works with a particular compiler
is not necessarily going to work with another, even on the same
platform. It is important that a learner be clear about the
differences between programming in standard C or C++, and
programming using platform- and compiler-specific extensions. In
the long run, this approach - that of separating the idea of
"language" and "platform" - leads to a better understanding of both
the language and the platform. It is generally accepted that the
sooner this is appreciated by the learner, the better. Usenet style
in general tends to be terse and to-the-point and this FAQ reflects
that, while attempting to be as fully informative as possible.
This is the only reason for grumpiness - most interested learners
find alt.comp.lang.learn.c-c++ a very pleasant and helpful place
once they understand this. The newsgroup is nowhere near as grumpy
as this FAQ might suggest - certainly not towards someone who has
read and understood all it has to say!
--
{ Sunil Rao }
"...certainly no beast has essayed the boundless, infinitely
inventive art of human hatred. No beast can match its range and
power." - Arundhati Roy, "The God of Small Things", 1997.
|
Закладки на сайте Проследить за страницей |
Created 1996-2024 by Maxim Chirkov Добавить, Поддержать, Вебмастеру |