While an older question that has been answered by many I believe a succinct method, not so different from the others posted, is to use a minor macro to help ease the duplication of class declarations.
// abstract.h
// Simply define the types that each concrete class will use
#define IMPL_RENDER() \
void render(int a, char *b) override { render_internal<char>(a, b); } \
void render(int a, short *b) override { render_internal<short>(a, b); } \
// ...
class Renderable
{
public:
// Then, once for each on the abstract
virtual void render(int a, char *a) = 0;
virtual void render(int a, short *b) = 0;
// ...
};
So now, to implement our subclass:
class Box : public Renderable
{
public:
IMPL_RENDER() // Builds the functions we want
private:
template<typename T>
void render_internal(int a, T *b); // One spot for our logic
};
The benefit here is that, when adding a newly supported type, it can all be done from the abstract header and forego possibly rectifying it in multiple source/header files.