Re: newbie on pointers

From:
Henrietta Denoue <henrietta@netcalcul.fr>
Newsgroups:
comp.lang.c++
Date:
Sun, 01 Apr 2007 23:03:36 +0200
Message-ID:
<eup2cv$2u9t$1@news01.tp.hist.no>
Thanks guys for the answer,
and sorry for the typo, I mean 'a' and 'b' as pointers, just
forgot the '*'.
For some reason function argument does not work. 'A' and 'B' have
of course destructors but do not touch 'x' in their destructors.
What 'A' does with x (x is an object with its own pointers
to other objects and arrays) is to process some data and fill in some
arrays inside 'x'. 'x' is actually a pointer to a an object of a class
that reads a file of certain format. The filename is transferred to
it through a gui. If the user change the file, of course 'x' is deleted
inside 'A' and a new 'x' is instantiated. But when I am finished with
'a' (deleted), the contents of 'x' is not what is
supposed to be. Therefore I gave up the idea of
using function arguments (I sent the address of
'x' to 'a' as an argument to a fuction).
So I switched to a shared /global variable. It seems to work but I
am not comfortable wit the idea. I would have preferred to do it
as I did first but it just didn't work.
H.

Henrietta Denoue wrote:

Hi,

What happens to a global pointer that is to be used in various
other objects, is instantiated in one object, then this second
object is deleted ? Is the pointer still valid ? like pseudo-code
---------------------------
// my global pointer, not a member of Classes A or B
X *x;

class A{
....
x = new X();

 ... do something with x

}

Class B {
...
do something with x;

}

int main()
{
A a;
B b;

a = new A();
....
delete a;

---------------

My question is : Is x still valid in B evenif A is deleted ?

Thanks,
H.

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