Strings in C++

allomeen · 01-20-2006, 11:13 AM

Hello everyone,

What is the difference between:
#include <string>, #include <string.h>, #include <String.h>.
I'm so confused about C++ string. Which one am I suppose to use in C++.

Can anybody just give description on how to get this to work, In some files #include <string.h> works for me fine, and in other files I had to put #include <string>. Which one is right for C++?

Thanks,
Alaa G

Flesym · 01-20-2006, 11:33 AM

this is deprecated for C++...

Code:

#include <string.h>

...so simply use always

Code:

#include <string>

Ha1f · 01-20-2006, 11:33 AM

In C++ you use #include <string>. <string.h> is from the standard C library, which means it's also available in C.

xhi · 01-20-2006, 11:34 AM

#include <string> c++ std::string
#include <string.h> c string lib
#include <cstring> for using c string in c++

<string>
ex.
string s = "this is a c++ string";
s += "appending this";

<string.h>
strcpy, strcmp, strcat ect.. C functions..

<cstring>
use the string.h inside of c++ the proper way..

hth

allomeen · 01-20-2006, 11:38 AM

Thanks guys,

What is String.h with capital "S"?

Alaa G

xhi · 01-20-2006, 11:38 AM

Quote:

Originally Posted by Flesym

this is deprecated...

Code:

#include <string.h>

...so simply use always

Code:

#include <string>

string.h is not deprecated.. it is the C string lib.. if you use
<string>
and
<string.h>
you get two separate things..

<string.h>
and
<cstring>
are the same thing but the proper way to use string.h in c++ is with
<cstring>

allomeen · 01-20-2006, 11:40 AM

Also sometimes I have #include<string.h> and C++ string works and I could do all string manipulation, but not all the time. Why is this happening?

How do you convert from char* to string?

Alaa G

xhi · 01-20-2006, 11:44 AM

>> How do you convert from char* to string?

Code:

char* a = "hello";
string b(a);

also i think the difference in String.h and string.h may be none.. i am not at home to try it, but in devcpp i get no errors when i do something like
#include <IoStReAm>

so maybe the case is not mattering..
I have not used String.h that is any different that i know of..

allomeen · 01-20-2006, 11:47 AM

Thanks xhi,
One more question, sorry i'm kinda new in C++. whenever you include in c++, you don't add .h, right?

and if I want to include something from C, do I add extern "C" {#include <something_in_C.h>}?

xhi · 01-20-2006, 11:48 AM

also operator=

Code:

char* a = "hello";
string b;
b=a;

that is why std::string is so nice..

Flesym · 01-20-2006, 11:52 AM

Quote:

string.h is not deprecated.. it is the C string lib.. if you use

string.h is(!) deprecated (at least for C++, I had already added this extra-piece in my earlier post), it is not part of C++ standard any more (once it was) -> so deprecated. But the problem is solved anyway, so who cares... ;-)

xhi · 01-20-2006, 11:57 AM

Quote:

Originally Posted by allomeen

Thanks xhi,
One more question, sorry i'm kinda new in C++. whenever you include in c++, you don't add .h, right?

and if I want to include something from C, do I add extern "C" {#include <something_in_C.h>}?

well not everything, but the new version of the std lib you dont.. so anything like iostream, string, fstream, etc... you do not..
with header files you create you will.. and other files that are not standard like for example from a graphics lib you are using or somthing like that..

i cannot help with the extern C as I have read the definition before, but have not found a use for it.. so I do not have the complete understanding of it..

xhi · 01-20-2006, 12:00 PM

Quote:

string.h is(!) deprecated (at least for C++, I had already added this extra-piece in my earlier post), it is not part of C++ standard any more (once it was) -> so deprecated. But the problem is solved anyway, so who cares... ;-)

the way you put it is not correct

Quote:

Originally Posted by Flesym

this is deprecated for C++...

Code:

#include <string.h>

...so simply use always

Code:

#include <string>

string.h and string are not and were not the same files..

string.h is deprecated for cstring not string

<edit> cstring and string.h contain the same functionality, just a namespace diff </edit>

allomeen · 01-20-2006, 12:05 PM

Thank you so much guys