有没有一种方法可以为std :: array创建功能模板专业化

Question

I have a function template

template<typename T>
void output(T& value)
{
}

Is there a way to create specialization for output std::array objects? Yes, I know, that arrays of different sizes are different types. ) I just hope that there is a way in c++11

Answer 1

template<class T, unsigned N>
void output(std::array<T,N>& value){
}

Would be what you should be using, since specializations are discouraged. Moreover, you can't partially specialize function templates.

Answer 2

You can't specialize it for all arrays, that would require a "partial specialization" of the template. A full specialization of a template pins down the values of all template parameters (in this case there is only one, T , so a full specialization only covers one type in place of T ). A partial specialization covers multiple possible values of the template parameters (in this case we want to cover any std::array<U,N> in place of T ), so a partial specialization has template parameters of its own.

C++ permits partial specialization of class templates but not of function templates.

Instead, you can overload it. You define another function template with the same name and different parameters:

template <typename T, size_t N>
void output (const std::array<T,N> &arr); // I guess "const" by the function name

Answer 3

You need an overload , not a specialization (there's just full specialization for function templates).

template <typename T, size_t N>
void output (std::array<T,N> &arr);

You are not allowed to put it into namespace std though. And if it just outputs data, you should not pass a non-const reference.

However, go the route the standard library goes, and use iterators instead:

template <typename Iter>
void output (Iter it, Iter end) 

This makes your function flexible wrt the container type: It probably does not need to know whether it's a list , deque or an array .