class Y; //not really relevant
class B
{
B(Y*);
//stuff
}
template<int SIZE> class X : public Y
{
B array[SIZE];
X();
}
I would like to call constructor of each element of array[] with this as parameter. How can I do that in pretty way? C++14 and even 17 are OK for me.
One of several approaches:
template <int SIZE>
class X : public Y
{
B array[SIZE];
template <std::size_t>
X* that() { return this; } // don't abuse the comma operator
template <std::size_t... Is>
X(std::index_sequence<Is...>) : array{ that<Is>()... } {}
public:
X() : X(std::make_index_sequence<SIZE>{}) {}
};
std::make_index_sequence and std::index_sequence? I can't find any docs for that but I've found an information somewhere that those are [std::integer_sequence`](en.cppreference.com/w/cpp/utility/integer_sequence) aliases...There's no "nice" or simple way of doing it with C arrays (or even std::array).
You can to it very easily if you change to use a std::vector instead. It has a constructor that allows you to set the size and pass the default value for all elements:
template<int SIZE> class X : public Y
{
std::vector<B> array;
X()
: array(SIZE, B(this))
{}
};
B(this), not clear if this suits OP's requirements