Re: More a C++ Q then vs... but why not?

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From: Alf P. Steinbach (alfps_at_start.no)
Date: 07/07/04 

Date: Wed, 07 Jul 2004 21:38:13 GMT

* Dead RAM:
> Well... Don't know C++ as well as a pro... so here goes...
>
>
> I want to do somthing like this:
>
> -------------------------------------------------------------------
> class someThing {
> public:
> // stuff, constructor, destructor, etc...
>
> private:
> const char myConstCharArrayInitializedAtObjectCreation[] =
> "blah";
> };

You can't have an array of indeterminate size as a member.

> --------------------------------------------------------------------
>
> After brute forcing my way through the errors I ended up with this:
>
>
> -------------------------------------------------------------------
> class someThing {
> public:
> // stuff, constructor, destructor, etc...
>
> private:
> const char* myConstCharArrayInitializedAtObjectCreation;
> };
>
> // more stuff
>
> someThing::someThing()
> : myConstCharArrayInitializedAtObjectCreation("blah")
> {
> // more stuff
> }

This is OK.

> -------------------------------------------------------------------
>
> I'm mainly wondering, in the second (and error free) version, is it the
> equivalent of the C statement:
>
> const char ch[]="blah"

No it isn't. What you have in class someThing is a pointer. What
you have right above is a character array.

 
> Umm... in other words, where is the "blah" data being stored

The "blah" has static storage.

The pointer to "blah" is being stored in your object.

One per object.

> and setup

?

> And am I running into a situation were the const char wasn't
> initialized properly and could potentialy lose the "blah" data

Not in the code presented here.

> (is the
> memory pointed to by the const char* valid, or does it just happend to work
> sometimes)?

In the code presented it is valid. 

-- 
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

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