arrays

[Amit Gulati]

Why is this valid in C++ ??

int *i = new int[];

I can access upto 4 elements using the int pointer.

If the dimension is not specified, then how many elements
are created??

Thanks

Amit

 

[Leor Zolman]

Why is this valid in C++ ??

int *i = new int[];

It isn't. MSVC, and perhaps some other implementations, allow it for the
benefit of legacy hacks (or perhaps simply because they haven't taken the
trouble to /disallow/ it, in the case where common internal compiler
machinations process both function array arguments and array-new
constructs), but it is not valid C++.
-leor

 

[Ivan Vecerina]

Why is this valid in C++ ??

int *i = new int[];

I don't think it is valid in ISO C++.
Which compiler accepts this syntax?
Did you try ANSI-strict mode?

I can access upto 4 elements using the int pointer.

Which might result from the fact that your platform
allocates memory blocks of at least 16 bytes (int being 4 bytes).

If the dimension is not specified, then how many elements
are created??

The new expression above is most likely returning, when accepted
by a compiler, an empty array. So dereferencing the returned
pointer will lead to undefined behavior.


Regards,
Ivan

 

[Amit Gulati]

Why is this valid in C++ ??

int *i = new int[];

It isn't. MSVC, and perhaps some other implementations, allow it for the
benefit of legacy hacks (or perhaps simply because they haven't taken the
trouble to /disallow/ it, in the case where common internal compiler
machinations process both function array arguments and array-new
constructs), but it is not valid C++.
-leor

I can access upto 4 elements using the int pointer.

If the dimension is not specified, then how many elements
are created??

Thanks

Amit

Thanks again!!