template< typename type_t, std::size_t N >
class Vector final
{
    public:

        Vector (void) noexcept = default;

        void generalMethod (void) noexcept;

    private:

        std::array< type_t, N > m_data = {0};
};

template< typename type_t, std::size_t N >
void
Vector< type_t, N >::generalMethod (void) noexcept
{
    // ... Do something
}

template<>
void
Vector< float, 4 >::generalMethod (void) noexcept
{
    // ... Do something
}