Hi, I need to define some strings in a header file, they are to be
const
Whats the best to choose from below;

const std::string s = "Hello";
const char* s = "Hello";
char* s = "Hello";

Thanks

tech wrote:
> Hi, I need to define some strings in a header file, they are to be
> const
> Whats the best to choose from below;
>
> const std::string s = "Hello";
> const char* s = "Hello";
> char* s = "Hello";
>
> Thanks

I am doing one of two:
const std::string s1 = "Hello";
const char* const s2 = "Hello";

On Jun 6, 3:53 pm, tech <naumansulai...@googlemail.com> wrote:
> Hi, I need to define some strings in a header file, they are
> to be const Whats the best to choose from below;

> const std::string s = "Hello";
> const char* s = "Hello";
> char* s = "Hello";

You can't really put the latter two in a header file without
getting duplicate definitions, since they aren't const. But you
ignore one of the most frequent alternatives:

char const s[] = "Hello" ;

It has the advantage of allowing static initialization, but does
mean that you'll probably end up having to construct an
std::string each time you use it, which tends to offset the
initial advantage of static initialization; but the static
initialization still has the advantage of avoiding order of
initialization problems, and the compiler can also ignore the
definition if you don't actually use the variable in a module.

--
James Kanze (GABI Software) email:james.kanze@gmail.com
Conseils en informatique orientée objet/
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On Jun 6, 4:02 pm, anon <a...@no.no> wrote:
> tech wrote:
> > Hi, I need to define some strings in a header file, they are
> > to be const Whats the best to choose from below;

> > const std::string s = "Hello";
> > const char* s = "Hello";
> > char* s = "Hello";

> I am doing one of two:
> const std::string s1 = "Hello";
> const char* const s2 = "Hello";

Why the pointer?

--
James Kanze (GABI Software) email:james.kanze@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34

anon wrote:
> tech wrote:
>> Hi, I need to define some strings in a header file, they are to be
>> const
>> Whats the best to choose from below;
>>
>> const std::string s = "Hello";
>> const char* s = "Hello";
>> char* s = "Hello";
>>
>> Thanks
>
> I am doing one of two:
> const std::string s1 = "Hello";
> const char* const s2 = "Hello";
Right, don't forget both the const's if you use char *
You want a constant pointer to a constant value.

Depending on your typical use, I would suggest const std::string, since
string adds so much utility.

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>

tech wrote:
> Hi, I need to define some strings in a header file, they are to be
> const
> Whats the best to choose from below;
>
> const std::string s = "Hello";

This is the only version here than can go in a header.

> const char* s = "Hello";

This has to be

const char* const s = "Hello";

Which you use depends on how you use them. If you wish to add to one
later (say it's a root file path), use std::string. If they are
discrete tokens, const char* const can be used. But do bear in mind a
std::string will be constructed each tome you pass one to a function
with a const std::string reference parameter.


--
Ian Collins.

On Jun 7, 11:27 pm, Ian Collins <ian-n...@hotmail.com> wrote:
> tech wrote:
> > I need to define some strings in a header file, they are to be
> > const
> > Whats the best to choose from below;

> > const std::string s = "Hello";

> This is the only version here than can go in a header.

Of the forms he proposes.

> > const char* s = "Hello";

> This has to be

> const char* const s = "Hello";

Again: what's wrong with:

char cosnt s[] = "Hello" ;

? Why do you need the extra pointer.

> Which you use depends on how you use them. If you wish to add
> to one later (say it's a root file path), use std::string. If
> they are discrete tokens, const char* const can be used. But
> do bear in mind a std::string will be constructed each time
> you pass one to a function with a const std::string reference
> parameter.

On the other hand, the std::string form may suffer from order of
initialization issues.

--
James Kanze (GABI Software) email:james.kanze@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34

James Kanze wrote:
> On Jun 7, 11:27 pm, Ian Collins <ian-n...@hotmail.com> wrote:
>> tech wrote:
>
>>> const char* s = "Hello";
>
>> This has to be
>
>> const char* const s = "Hello";
>
> Again: what's wrong with:
>
> char cosnt s[] = "Hello" ;
>
It won't compile?

> ? Why do you need the extra pointer.
>
No particular reason, just habit. I'm just used to thinking of a
constant pointer to a string literal. A string literal has to have an
address, so where's the extra pointer?

--
Ian Collins.