// all freestandingnamespace std {template<class E>class initializer_list {public:using value_type = E;
using reference =const E&;
using const_reference =const E&;
using size_type = size_t;
using iterator =const E*;
using const_iterator =const E*;
constexpr initializer_list()noexcept;
constexprconst E* data()constnoexcept;
constexpr size_t size()constnoexcept; // number of elementsconstexprbool empty()constnoexcept;
constexprconst E* begin()constnoexcept; // first elementconstexprconst E* end()constnoexcept; // one past the last element};
}