On 2 May 2003 at 8:27, Jerry Feldman wrote: Date sent: Fri, 2 May 2003 08:27:02 -0400 From: Jerry Feldman To: suse-programming-e@suse.com Organization: Boston Linux and Unix Subject: Re: [suse-programming-e] c++ array problem

On Fri, 2 May 2003 11:50:21 +0000 Gedi wrote:

...

I've just started to learn C++ in the last few days and have some accross a small problem. Here is a few corrections to your code: #include <iostream> #include <iomanip> using std::cout; using std::cin; using std::endl; int ix, array[10];

int main() { for(ix = 0; ix < 10; ix++) { cout << "Enter string: "; cin >> array[ix];

}

// cout << array; // a little unsure as to how you print the strings out as a whole and seperatly cout << array[1] << endl; cout << array[3] << endl; return 0; }

My changes are: 1. remove the .h for the header files. The older headers are deprecated. 2. cin and cout are in namespace std. You could have used "using namespace std;" as an alternative. 3. index is a Linux function and declared in string.h which is implicitly included. 4. Make sure you have line endings. It is best to use endl from the iomanip header rather than '\n', but '\n' or "\n" woould have worked fine also. 5. You cannot print an entire array unless the class includes the appropriate friend functions overloading the << operator. Since int is a basic type, there is no support for it in the language. In your case, cout << array << endl; will print out the address of the array. 6. Your "Enter string" comment is a bit of a misnomer. You should ask for a number since you are entering and int. 7. main should return something.

I suggest you get a good book on C++. Bruce Eckel's Thinking in C++ is available online: http://www.mindview.net/Books/TICPP/ThinkingInCPP2e.html Additionally another book I use is "The C++ Primer". Several books on C++ have been discussed on this forum, and you can check the archives. -- Jerry Feldman Boston Linux and Unix user group http://www.blu.org PGP key id:C5061EA9 PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9

C++ Primer is very good - I recommend it too. Also, in addition to Jerry's comments you might like to consider that you should probably be using a vector container, rather than an array... alan -- http://www.ibgames.net/alan Registered Linux user #6822 http://counter.li.org Winding Down - Weekly Tech Newsletter - subscribe at http://www.ibgames.net/alan/winding/mailing.html

On Saturday 03 May 2003 07:11, Jerry Feldman wrote:

On Sat, 03 May 2003 08:31:05 +0100

alan@ibgames.com wrote:

...

C++ Primer is very good - I recommend it too. Also, in addition to Jerry's comments you might like to consider that you should probably be using a vector container, rather than an array...

I would agree with this if this was a real problem. But, Gedi is just learning C++, and probably should learn the basics before using the features of the STL. =====================

Not to hijack a thread and I don't remember if this was mentioned earlier, but who are the authors of the C++ Primer and what edition? I did find some hits when doing a search, but there seems to be more than one listed all with different authors. I know Jerry has been involved with C & C++ for a while now, so I thought he would know exactly. Thanks Patrick -- --- KMail v1.5.9.1i --- SuSE Linux Pro v8.2 --- Registered Linux User #225206 On any other day, that might seem strange...

On 3 May 2003 at 12:06, Jerry Feldman wrote: Date sent: Sat, 3 May 2003 12:06:47 -0400 From: Jerry Feldman To: suse-programming-e@suse.com Organization: Boston Linux and Unix Subject: Re: [suse-programming-e] c++ array problem

On Sat, 3 May 2003 10:33:25 -0400 "O'Smith" wrote:

...

Not to hijack a thread and I don't remember if this was mentioned earlier, but who are the authors of the C++ Primer and what edition? I did find some hits when doing a search, but there seems to be more than one listed all with different authors. I know Jerry has been involved with C & C++ for a while now, so I thought he would know exactly. Stanley B. Lippman and Josee Lajoie Publisher: Addison Wesley. The latest edition appears to be the Third Edition. -- Jerry Feldman

The third edition is the most recent published. Stan has just started work on the fourth edition, but I would guess it will be a while before it's out. alan -- http://www.ibgames.net/alan Registered Linux user #6822 http://counter.li.org Winding Down - Weekly Tech Newsletter - subscribe at http://www.ibgames.net/alan/winding/mailing.html

On Saturday 03 May 2003 22:01, alan@ibgames.com wrote:

Ah! The eternal discussion - when should the STL be introduced to people learning C++ :)

I think NOW would be perfect. Here are yet a few improvements to Feldman's implementation: #include <iostream> #include <vector> #include <algorithm> #include <iterator> int main() { using std::vector; using std::cout; using std::flush; using std::cin; using std::copy; using std::ostream_iterator; vector<int> array(10); for (int i = 0; i < 10; ++i) { cout << "Enter number: " << flush; cin >> array[i]; } copy(array.begin(), array.end(), ostream_iterator<int>(cout, "\n")); } 1. Yes, vector<> should be used in favor of C style arrays 2. <iomanip> is not needed for std::endl or std::flush 3. '\n' is preferred over std::endl, if stream flushing is not desired 4. (I think) cout is flushed upon destruction, i.e., at program exit 5. 'using' directives should be avoided in global scope 6. global variables should generally be avoided 7. main() returns 0 if not otherwise stated 8. I'm not intending to shine with my implementation, but I do certainly think that the standard library should be studied from the beginning, together with the rest of the language. C++ is not simply 'C with classes'. It is a complete language of its own, with a very powerful standardized library. 9. Besides Lippman-Lajoie, I'd like to push for the following titles: - Stroustrup: The C++ Programming Language, 3rd Edition, Addison-Wesley - Josuttis: The C++ Standard Library, Addison-Wesley -- Ch

On Sun, 04 May 2003 07:23:00 +0100 alan@ibgames.com wrote:

Hmmm... I hope people don't think this is hijacking the thread :) No. I for one appreciate the feedback.

-- Jerry Feldman Boston Linux and Unix user group http://www.blu.org PGP key id:C5061EA9 PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9

Ah! The eternal discussion - when should the STL be introduced to people learning C++ :) One needs to have a good foundation in a language before using things

On Sat, 03 May 2003 21:01:26 +0100 alan@ibgames.com wrote: like the STL. But, it is important to understand the STL also. Vectors, trees, stacks and many other template classes you can build on. One can say the same thing about arithmetic. You should learn to add, subtract, divide and multiply before you use a calculator. -- Jerry Feldman Boston Linux and Unix user group http://www.blu.org PGP key id:C5061EA9 PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9

On Sat, 3 May 2003 16:46:05 +0100 "Gedi" wrote:

Another quick question for anyone before the books arrive, how would you get the array to take strings. I obviously changed from int to char, but instead of holding full words, it holds the characters of each word. I have Practical C++ Programming, but have not had time to read it yet.

There is a C++ string type in the standard library. You can crwate an array of these. Just add #include <string> and using std::string; And change int array[10] to string array[10] The rest of the code with my corrections should work fine. However, I think that you might want to look more toward creating classes. -- Jerry Feldman Boston Linux and Unix user group http://www.blu.org PGP key id:C5061EA9 PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9