Re: Lets put it another way

From:

Ian Collins <ian-news@hotmail.com>

Newsgroups:

comp.lang.c++

Date:

Wed, 25 May 2011 07:36:31 +1200

Message-ID:

<942fm0Fuc5U1@mid.individual.net>

On 05/25/11 12:58 AM, Paul wrote:

"Ian Collins"<ian-news@hotmail.com> wrote in message
news:941ffpFt2pU22@mid.individual.net...

On 05/24/11 09:20 PM, Paul wrote:

"Ian Collins"<ian-news@hotmail.com> wrote in message
news:940g82Ft2pU20@mid.individual.net...

On 05/24/11 01:14 PM, Paul wrote:

Ok in connection to my previous post, lets remove the null pointer
issue
and
consider this:

#include<iostream>

typedef int (*pparr)[3];

int main(){
    pparr p1 = (pparr)new int[3];
    pparr p2= p1;
    delete[] p1;
    std::cout<< *p2<<std::endl;

UB yet again.

std::cout<< typeid(*p2).name();
}

In the last 2 lines does an array type object exist, even though there
is
no
array object?

No.

If not what is the object that stores the address and is interpreted as
an
array type by the typeid expression?

The typeid and sizeof operators do not evaluate their expression (unless
in case of typeid the type is polymorphic). So no object is required.

You do not seem to understand the question.

You do not appear to understand the answer.

I said ..if not what is the object that stores the address?
So what is this object? Do you know?

There isn't an object. The compiler knows the type of *p2. You may as
well have written

#include<iostream>
#include<typeinfo>

typedef int (*pparr)[3];

int main(){
pparr p2;
std::cout<< typeid(*p2).name()<< std::endl;
}

You are not addressing the what stores the memory address.

Because there isn't an address to store. The typeid operator (like
sizeof) works with types, not values. In a simple case such as this the
operand is not evaluated. Until you understand this you will be stuck
in limbo.

I could have simplified my simplification further by writing

std::cout << typeid(int[3]).name() << std::endl;

See? No memory address just a type.

A memory address value is stored so there must be an object to store this
value, you say there is no object so what is it that stores this value?

There isn't an address. Where's the address in typeid(int).name()? Or
sizeof(int)?

--
Ian Collins