How to specialize only some members of a template class?

Question

Code:

template<class T>
struct A {
  void f1() {};
  void f2() {};

};

template<>
struct A<int> {
  void f2() {};
};


int main() {
  A<int> data;
  data.f1();
  data.f2();
};

ERROR:

test.cpp: In function 'int main()':
test.cpp:16: error: 'struct A<int>' has no member named 'f1'

Basically, I only want to specialize one function and use the common definition for other functions. (In actual code, I have many functions which I don't want to specialize).

How to do this? Thanks!

Answer 1

Consider moving common parts to a base class:

template <typename T>
struct ABase
{
    void f1();
};


template <typename T>
struct A : ABase<T>
{
    void f2();
}  


template <>
struct A<int> : ABase<int>
{
    void f2();
};

You can even override f1 in the derived class. If you want to do something more fancy (including being able to call f2 from f1 code in the base class), look at the CRTP.