c++ - specializing member S::display requires ‘template<>’ syntax

Question

I'm creating a trait class to help with my program. I have a template class called operations that contains the methods display and area. When I define these functions I get errors. Here they are:

error: specializing member ‘traits::operations<Rectangle>::display’ requires ‘template<>’ syntax
error: specializing member ‘traits::operations<Rectangle>::area’ requires ‘template<>’ syntax

As you can see, the compiler wants me to insert template <> just before those definitions. But when I do, I get a huge page of errors. What's going wrong and how can I fix it?

Here is my program.

namespace traits
{
    template <typename P>
    struct operations
    {
        static void display(Rectangle const &, std::ostream &);
        static void area(Rectangle const &);
    };

    template <typename P, int N>
    struct access {};
}

namespace traits
{
    template <int N>
    struct access<Rectangle, N>
    {
        static double get(Rectangle const &);
    };
}

// The errors occur here
namespace traits
{
    static void operations<Rectangle>::display(Rectangle const &rect, std::ostream &os)
    {
        os << rect.width  << '
';
        os << rect.height << '
';
        os << area(rect)  << '
'; 
    }

    static void operations<Rectangle>::area(Rectangle const& rect)
    {
        double width =  get<0>(rect);
        double height = get<1>(rect);

        return width * height;
    }
}

namespace traits
{
    template <>
    struct access<Rectangle, 0>
    {
        static double get(Rectangle const &rect)
        {
            return rect.width;
        }
    };

    template <>
    struct access<Rectangle, 1>
    {
        static double get(Rectangle const &rect)
        {
            return rect.height;
        }
    };
}

template <int N, typename P>
static inline double get(P const &p)
{
    return traits::access<P, N>::get(p);
}

template <typename P>
static inline void display(P const &p)
{
    traits::operations<P>::display(p, std::cout);
}

template <typename P>
static inline double area(P const &p)
{
    return traits::operations<P>::area(p);
}

int main()
{

}

Here is a program which shows the error - http://ideone.com/WFlnb2#view_edit_box

Any and all help is appreciated.

---

Thanks to help from the comments I got rid of those two errors, but I'm not getting more after adding the template<> declaration and fixing the return type of area:

error: cannot declare member function ‘static void traits::operations<P>::display(const Rectangle&, std::ostream&) [with P = Rectangle; std::ostream = std::basic_ostream<char>]’ to have static linkage [-fpermissive]
error: explicit template specialization cannot have a storage class
error: specialization of ‘static double traits::operations<P>::area(const Rectangle&) [with P = Rectangle]’ after instantiation
error: explicit template specialization cannot have a storage class

Answer 1

Your functions : display and area should be write like this:

    template <>
    double operations<Rectangle>::area( Rectangle const& rect )
    {
            double width =  get<0>(rect);
            double height = get<1>(rect);

            return width * height;
    }

• As for template specialized functions, template <> should be placed at the head of the function.
• For static member functions, static should not appear at the definition body of the function.