can someone explain the difference and tell me which of these should i be using ? #include <iostream.h> cout << " "; etc. //------------------ #include <iostream> using namespace sdt; // or using sdt::cout etc. cout << " "; // or sdt::cout etc. very confusing, i have been using #include <iostream.h> because i was using an older book, and thats what they were using, i got given a newer book and it uses #include <iostream> im tempted to continue to use iostream.h someone tell me why i shouldnt do this ?

Use #include <iostream>

[edited by - neurokaotix on January 3, 2003 7:51:52 PM]

#include<iostream>

is correct.

#include<iostream.h>

is not.

#include <iostream> // The way of the future
using namespace std; // ditto

#include <iostream.h> // In case the future has not yet arrived

adding the .h is the old C++ style, and may be used if you are using an old compiler, or else, you should stick to #include <iostream>

[Edit]: Noticed u got more.. ok

cout is a output message code that can write whatever that is in the "". the << is for output, and >> is for input (text you write). If you do not use the ; at the end, you will get an error, because the compiler thinks that the whole cout << "" is a header, and it's not.

Strip it down, and the code will be:

int main() - Header
{ - start function
statement ( cout << ""; )
return 0; - because it's just so that u must use it in int main()
} - terminate function

It's a bit hard to understand in the beginning, but u will understand it later

std::cout and so is special.. instead of using a long list of std's (cout, cin etc.), u can be lasy, and write :
using namespace std;

so the list is shortened.
But the problem is, if you have an old compiler, it might not regognise the new c++ style with: using namespace std;
and that's where you have to use std::cout

and // is comments.. you can also use /* comment */

Hope that helps! and don't lose hope.. Can you believe I am a newbie with the book "C++ Primer Plus Fourth Edition" by Stephen Prata, And I just started yesterday? :D



[edited by - wolferey on January 3, 2003 8:16:07 PM]

but why?

The old-style headers such as were written prior to the C++ standardisation. They are not part of the C++ standard. is part of the standard C++ library. Therefore, the former is not guaranteed to be supplied with a C++ compiler (if it is, this is only for the sake of legacy compatibility), while the latter is. In short: The former is old, deprecated, and may or may not work with any given compiler; the latter is up-to-date and part of the standard. It also makes use of namespaces.

hehe wolferey i was just wondering what was the difference between iostream.h and iostream,

im currently trying to understand virtual copy constructors, got bored so took a break (btw i love reading c vs c++ threads they really get people going dont they ), iostream/iostream.h had been bothering me, i knew how to use both, my compiler works with both, while i was here i thought i would find out which i should be using.

got the answer now so thanx.

Np.. That''s what the forums are for.. to learn and get help.. right? right people..? Stop looking so wierd at me.. *runs and hides*

something that I never understood was I started off with in the current program I''m working on and got it to compile fine. As soon as I changed it to I got 14 compile errors! Why is that.

-----------------------------
Programming is confussing!
AIM: Trebor DoD

quote: Original post by Digigamer15
something that I never understood was I started off with in the current program I''m working on and got it to compile fine. As soon as I changed it to I got 14 compile errors! Why is that.

Among other things, as with (theoretically) all other standard C++ headers, <iostream> puts its declarations in the std namespace. Either prefix every use of symbols it declares with std:: (e.g. std::cout) to fully scope them, or add a using namespace std; declaration in your .cpp file. It is strongly advised to always use fully scoped declarations in header files (i.e. don''t put a using namespace std; in a .h file), since doing otherwise defeats the purpose of namespaces.

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