template <class T>
class optional
{
public :
    typedef T         value_type ;
    typedef T &       reference_type ;
    typedef T const&  reference_const_type ;
    typedef T &&      rval_reference_type ;
    typedef T *       pointer_type ;
    typedef T const*  pointer_const_type ;
    optional () noexcept ; 
    optional ( none_t ) noexcept ; 
    optional ( T const& v ) ; 
    optional ( T&& v ) ; 
    // [new in 1.34]
    optional ( bool condition, T const& v ) ; 
    optional ( optional const& rhs ) ; 
    optional ( optional&& rhs ) noexcept(see below) ; 
    template<class U> explicit optional ( optional<U> const& rhs ) ; 
    template<class U> explicit optional ( optional<U>&& rhs ) ; 
    template<class InPlaceFactory> explicit optional ( InPlaceFactory const& f ) ; 
    template<class TypedInPlaceFactory> explicit optional ( TypedInPlaceFactory const& f ) ; 
    optional& operator = ( none_t ) noexcept ; 
    optional& operator = ( T const& v ) ; 
    optional& operator = ( T&& v ) ; 
    optional& operator = ( optional const& rhs ) ; 
    optional& operator = ( optional&& rhs ) noexcept(see below) ; 
    template<class U> optional& operator = ( optional<U> const& rhs ) ; 
    template<class U> optional& operator = ( optional<U>&& rhs ) ; 
    template<class... Args> void emplace ( Args&&... args ) ; 
    template<class InPlaceFactory> optional& operator = ( InPlaceFactory const& f ) ; 
    template<class TypedInPlaceFactory> optional& operator = ( TypedInPlaceFactory const& f ) ; 
    T const& get() const ; 
    T&       get() ; 
    T const* operator ->() const ; 
    T*       operator ->() ; 
    T const& operator *() const& ; 
    T&       operator *() & ; 
    T&&      operator *() && ; 
    T const& value() const& ; 
    T&       value() & ; 
    T&&      value() && ; 
    template<class U> T value_or( U && v ) const& ; 
    template<class U> T value_or( U && v ) && ; 
    template<class F> T value_or_eval( F f ) const& ; 
    template<class F> T value_or_eval( F f ) && ; 
    T const* get_ptr() const ; 
    T*       get_ptr() ; 
    explicit operator bool() const noexcept ; 
    bool operator!() const noexcept ; 
    // deprecated methods
    // (deprecated)
    void reset() noexcept ; 
    // (deprecated)
    void reset ( T const& ) ; 
    // (deprecated)
    bool is_initialized() const ; 
    // (deprecated)
    T const& get_value_or( T const& default ) const ; 
};