question about initial values

[mclark]

Ok, another question for the Standards weenies...

I'm pretty sure I know the answer (A) but I'm gonna ask anyways.

given...

std::vector<int *> Vec(1);

Vec is constructed using:
vector(size_type n,
value_type const & value = value_type(),
allocator_type const & allocator = allocator_type());


is the value of Vec[0] = ?
(A) undefined
(B) null/0

This is more easily phrased as "what is the value of a default constructed pointer when constructor syntax is explicitly used?"

[Codeplug]

B.

From ISO/IEC FDIS 14882:1998(E) (Final Draft), section 8.5.7

8.5 - Initializers [dcl.init]
...
-5- ... To default-initialize an object of type T means:
* if T is a non-POD class type (clause class), the default constructor for T is called (and the initialization is ill-formed if T has no accessible default constructor);
* if T is an array type, each element is default-initialized;
* otherwise, the storage for the object is zero-initialized.
...
-7- An object whose initializer is an empty set of parentheses, i.e., (), shall be default-initialized.

I woudn't count on your compiler being 100% standards conforming......we all know what assume spells

gg

[mclark]

Beautiful,

This is exactly the type of succinct and definitive response I was looking for. Thanks for correcting my mistaken assumption!