What is wrong in this template definition?

Question

template <int N>
class myarray {
    typedef int Bitmap;
public:
    static Bitmap data[N];
};

template <int N> myarray<N>::Bitmap myarray<N>::data[N];

error: expected constructor, destructor, or type conversion before ‘myarray’

Relevant: http://stackoverflow.com/questions/610245/where-and-why-do-i-have-to-put-the-template-and-typename-keywords — R. Martinho Fernandes, Dec 20 '11 at 01:18
Now for a stupid follow up question: Why not just delete the last line? Isn't that just a redundant second declaration? — Aaron McDaid, Dec 20 '11 at 01:38
Doh! I see now. Undefined references. It's the required *definition*, whereas the earlier line is just the *declaration*. — Aaron McDaid, Dec 20 '11 at 01:40

score 9 · Accepted Answer · answered Dec 20 '11 at 01:14

You need typename before myarray<N>::Bitmap because it is a dependent type:

template <int N>
class myarray {
    typedef int Bitmap;
public:
    static Bitmap data[N];
};

   template <int N>
   typename myarray<N>::Bitmap myarray<N>::data[N];
// ^^^^^^^^

What is wrong in this template definition?

1 Answers1