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  1. class Base
  2. {
  3.     // Note: You can make this protected, but then you need `friend class Common;` in A, B.
  4. public:
  5.     int x, y;
  6. };
  7.  
  8. struct Common
  9. {
  10.     // Hide implementation details here, has access data of type T
  11.     // (only public stuff can be accessed, unless Common is a friend of T!)
  12.     template <class T>
  13.     int sum(T *_this) const {
  14.         return _this->x + _this->y;
  15.     }
  16. };
  17.  
  18. class A : public Base, private Common
  19. {
  20. public:
  21.     // Only forward to the actual implementation in Common
  22.     int sum() const { return Common::sum(this); }
  23. };
  24.  
  25. class B : public Base, private Common
  26. {
  27. public:
  28.     // Only forward to the actual implementation in Common
  29.     int sum() const { return Common::sum(this); }
  30. };
  31.  
  32.  
  33. int main() {
  34.     return 0;
  35. }
Success #stdin #stdout 0s 2892KB
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https://ideone.com/wFDygc
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
secret

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