lst-0029-book.cpp
// https://godbolt.org/z/Kvfx9Yeox
#include <array>
class Value {
int val_;
public:
constexpr Value(int val) : val_{val} {};
constexpr int get() const { return val_; }
};
constexpr Value five{5}; // works, Value is a literal data type
std::array<int,five.get()> data; // works, get is constexpr