c ++类模板（默认）

Question

I am trying to do something like this. but cannot figure out the right syntax .. any help would be greatly appreciated

template <typename T, typename K = UINT32>
class info
{
   K* asArray();
}

template <typename T, typename K = UINT32>
K* info<T, UINT32>:: asArray() { // return a int array };

template <typename T, char>
char* info<T, char>:: asArray() { // return a char array };

Answer 1

This is all you need - put the definition into the class template.

template <typename T, typename K = int>
class info {
  K* asArray(){ return 0; }
};

A specialisation of the class member alone is possible via eg

template<>
char* info<int,char>::asArray(){ return new char[10]; }

This overrides the basic definition in the class template:

info<int,char> iv;
char* iptr = iv.asArray();
if( iptr != 0 ) std::cout << "ok - not null" << std::endl;

Displays ok - not null .

Answer 2

You cannot have a partial specialization of a member function only. You have to create a specialization of the class itself.

template <typename T>
class info<T, char>
{
   char* asArray();
};

Then, you can use:

template <typename T>
char* info<T, char> asArray  { // return a char array }

This is not allowed:

template <typename T, typename K = UINT32>
K* info<T, UINT32>:: asArray() { // return a int array };

You have to use:

template <typename T, typename K>
K* info<T, K>:: asArray() { // return a K array };