Question

I have a templated struct with some enumerations in it and I’d like to make a std::array with the enumerations in it for convenience. Is there any way of doing the following?

template< typename A >
struct someClass{
    enum class State{
        sA,
        sB,
        sC
    }

    static const std::array<State,4> the_states = {{
        State::sA,
        State::sB,
        State::sC
    }};

};

Answer 1

No. Only static const integral data members can be initialized within a class.

However, you could do this…

template< typename A >
struct someClass
{
    enum State
    {
        sA,
        sB,
        sC
    };

    static const std::array<const State,4> the_states;
};

template<typename A>
const std::array<const someClass::State,4> someClass<A>::the_states = 
{
    someClass::State::sA, 
    someClass::State::sB, 
    someClass::State::sC 
};