oop - Implementing multiple interfaces in c++ -

i have interface hierarchy follows:

class { public:  void foo() = 0; };  class b: public { public: void testb() = 0; };  class c: public { public: void testc() = 0; }; 

now, want implement these interfaces same hierarchy, base class aimpl, bimpl , cimpl not sure how derive them corresponding interfaces.

please help. in advance.

you can implement each individial interface using separate template , chain templates construct derived object if building blocks. method used venerable atl library implement com interfaces (for of old enough).

note don't need virtual inheritance that.

i modified example more complex derivation c -> b -> a show how method scales easily:

#include <stdio.h>  // interfaces  struct {     virtual void foo() = 0; };  struct b : {     virtual void testb() = 0; };  struct c : b {     virtual void testc() = 0; };  // implementations  template<class i> struct aimpl : {     void foo() { printf("%s\n", __pretty_function__); } };  template<class i> struct bimpl : {     void testb() { printf("%s\n", __pretty_function__); } };  template<class i> struct cimpl : {     void testc() { printf("%s\n", __pretty_function__); } };   // usage  int main() {     // compose derived objects templates building blocks.     aimpl<a> a;     bimpl<aimpl<b> > b;     cimpl<bimpl<aimpl<c> > > c;      a.foo();      b.foo();     b.testb();      c.foo();     c.testb();     c.testc(); } 

output:

void aimpl<i>::foo() [with = a] void aimpl<i>::foo() [with = b] void bimpl<i>::testb() [with = aimpl<b>] void aimpl<i>::foo() [with = c] void bimpl<i>::testb() [with = aimpl<c>] void cimpl<i>::testc() [with = bimpl<aimpl<c> >]