static array initialization

[Makis Papapanagiotou]

Hello,

I really don't understand the simplest thing at the moment. I have a static
array of pointers to a class . How do we initialize it?

class classA
{
public:
int x1;
};

class classB
{
public:
void foo() { cout<< m_ptr[0]->x1; }
static classA* m_ptr[4];
};

classA* classB::m_ptr[0]=0; // This is not correct !!!
classA* classB::m_ptr[1]=0; // This is not correct !!!
classA* classB::m_ptr[2]=0; // This is not correct !!!
classA* classB::m_ptr[3]=0; // This is not correct !!!

int main()
{
classB* ptr = new classB;

ptr->foo();

return 0;
}

Any idea? If "m_ptr" was not an array of pointers I would had initialize it
like this: "classA* classB::m_ptr=0 ;"
What about arrays now?

[John Harrison]

Re: static array initialization


"Makis Papapanagiotou" <Serafim.Papapa nagiotou@siemen s.com> wrote in message
news:bj409b$hkt $1@news.mch.sbs .de...[color=blue]
> Hello,
>
> I really don't understand the simplest thing at the moment. I have a[/color]
static[color=blue]
> array of pointers to a class . How do we initialize it?
>
> class classA
> {
> public:
> int x1;
> };
>
> class classB
> {
> public:
> void foo() { cout<< m_ptr[0]->x1; }
> static classA* m_ptr[4];
> };
>
> classA* classB::m_ptr[0]=0; // This is not correct !!!
> classA* classB::m_ptr[1]=0; // This is not correct !!!
> classA* classB::m_ptr[2]=0; // This is not correct !!!
> classA* classB::m_ptr[3]=0; // This is not correct !!!
>
> int main()
> {
> classB* ptr = new classB;
>
> ptr->foo();
>
> return 0;
> }
>
> Any idea? If "m_ptr" was not an array of pointers I would had initialize[/color]
it[color=blue]
> like this: "classA* classB::m_ptr=0 ;"
> What about arrays now?
>[/color]

Same way you initialise any array

classA* classB::m_ptr[4] = { 0, 0, 0, 0 };

but since zero initialisation is the default, you don't need to initialise
it at all.

classA* classB::m_ptr[4];

john

[Josephine Schafer]

Re: static array initialization


"Makis Papapanagiotou" <Serafim.Papapa nagiotou@siemen s.com> wrote in message
news:bj409b$hkt $1@news.mch.sbs .de...[color=blue]
> Hello,
>
> I really don't understand the simplest thing at the moment. I have a[/color]
static[color=blue]
> array of pointers to a class . How do we initialize it?
>
> class classA
> {
> public:
> int x1;
> };
>
> class classB
> {
> public:
> void foo() { cout<< m_ptr[0]->x1; }
> static classA* m_ptr[4];
> };
>
> classA* classB::m_ptr[0]=0; // This is not correct !!!
> classA* classB::m_ptr[1]=0; // This is not correct !!!
> classA* classB::m_ptr[2]=0; // This is not correct !!!
> classA* classB::m_ptr[3]=0; // This is not correct !!![/color]

Try this -
classA* classB::m_ptr[]={0};