new-initializers for an array

Join Bytes! wrote:

No. There can be no expression between the parentheses
following the bracketed expression in the 'new' expression.
It can only be

A* p = new A[10]();

If you need to initialise all your elements to a particular
value (int in your case), you would have to use some kind
of "indirect initialiser" trick, like this:

#include <iostream>
struct A
{
static int initialiser;
A(int i = initialiser) // this could be used as
{ // your default c-tor as well
std::cout << i << std::endl;
}

};

int A::initialiser = 42;

int main()
{
A* p42 = new A[10](); // initialises with what's there
A::initialiser = 99; // set the "what's there" to 99
A* p99 = new A[10](); // initialises with what's there
}

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

Join Bytes! wrote:

No, arrays are always initialized with the default ctor.

D.

Join Bytes! wrote:


And:
<http://www.parashift.com/c++-faq-lite/ctors.html#faq-10.5>

Best, Dan.

"""Victor Bazarov ÐÉÓÁÌ(Á):
"""

Could you please point to the relevant paragraph?

Join Bytes! wrote:

5.3.4/15.

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

Join Bytes! wrote:

5.3.4/15

--
Best regards,
Andrey Tarasevich

Join Bytes! wrote:

No, but if you need the above, simply do it in the default ctor.

struct A
{
int a;
public:
A() : a(99) { }
};

// And you don't need new at all.

int main()
{
A array[10]; // 10 elements set to 99
}

A better alternative: std::vector< int vn(10, 99);

Join Bytes! wrote:

Add a copy constructor to A then take a look at std::allocator and
std::vector

Regards,
Ben