How to specialize only some members of a template class?

Question

Code:

template
struct A {
  void f1() {};
  void f2() {};

};

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


int main() {
  A<         


        

Answer 1

Would this help:

template<typename T>
struct A
{
  void f1()
  {
    // generic implementation of f1
  }
  void f2()
  {
    // generic implementation of f2
  }
};

template<>
void A<int>::f2()                                                               
{
  // specific  implementation of f2
}

Answer 2

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.

Answer 3

When we declare specializations for a template class, we must also define all its members, even those exactly equal to the generic template class, because there is no inheritance of members from the generic template to the specialization. So, in your specialization you have to implement void f1(); too.