Suppose I have a class template like this:
template<typename T, size_t N>
struct S {
std::array<T,N> a;
};
Is there a default member initializer I can place on a,
template<typename T, size_t N>
struct S {
std::array<T,N> a = ???;
};
such that no matter what T is, the elements of a will always be initialized (never have indeterminant value)? I.e., even if T is a primitive type like int.
This:
template<typename T, size_t N>
struct S {
std::array<T,N> a = {};
};
That will recursively copy-initialize each element from {}. For int, that will zero-initialize. Of course, someone can always write:
struct A {
A() {}
int i;
};
which would prevent i from being initialized. But that's on them.
std::array is an aggregate type. You can aggregate initialize it with empty braces {} and that will initialize accordingly the elements of the internal array of T that std::array holds.
