Is 'operator new[]' supposed to call the default constructor on POD?

[Richard.J]

I am using VS2010 and am checking how operator new[] behaves for POD like int. The following code produces this output in a release build:
340178 340178 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

#include <iostream>

int main()
{
    int *in = new int[20];

    std::cout << std::hex;
    for ( int i = 0; i < 20; ++i )
    {
        std::cout << in[i] << " ";
    }
    std::cout << std::endl;

    delete[] in;
}

In debug build, the output is
cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd cdcdcdcd
which does not surprise me.

I was thinking that operator new[] calls the default constructor int() and all values in the array should have a value of 0. Am I missing something here?

Thanks,
Richard

[superbonzo]

no, in an expression "new T[20]" T is default-initialized that for POD means having an unspecified value ( as in the expression "T t;" ).
What you want is called value-initialization: the syntax in the array case is "new T[20]()" ( or "new T[20]{}" in newest compilers ) ( as in "T t = T();" or "T t{};") that for POD means being zero-initialized.

[Richard.J]

Ah, thanks superbonzo. This works like I want it to.

The reason I asked is I have some legacy code which either uses new[] or even malloc and then sets the values to 0 or calls memset. I was thinking about a better way...