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  1. #include <iostream>
  2.  
  3. using namespace std;
  4.  
  5. class Base {
  6. public:
  7.     virtual ~Base() {}
  8.     virtual void func1() {}
  9.     virtual void func2() {}
  10.     virtual void func3() {}
  11.  
  12. };
  13.  
  14. template<class B> class Derived1 : public B {
  15. public:
  16.     virtual void func1() {
  17.         cout << "Derived1" << endl;
  18.     }
  19. };
  20.  
  21. template<class B> class Derived2 : public B {
  22. public:
  23.     virtual void func2() {
  24.         cout << "Derived2" << endl;
  25.     }
  26. };
  27.  
  28. template<class B> class Derived3 : public B {
  29. public:
  30.     virtual void func3() {
  31.         cout << "Derived3" << endl;
  32.     }
  33. };
  34.  
  35. typedef Derived1<Derived2<Base> > Foo;
  36. typedef Derived2<Derived3<Base> > Qoo;
  37. typedef Derived1<Derived1<Base> > Hoo;
  38.  
  39. int main() {
  40.  
  41.     Base *foo = new Foo;
  42.     foo->func1();
  43.     foo->func2();
  44.     foo->func3();  // do nothing
  45.     cout << "---------" << endl;
  46.  
  47.     Base *qoo = new Qoo;
  48.     qoo->func1();  // do nothing
  49.     qoo->func2();
  50.     qoo->func3();
  51.     cout << "---------" << endl;
  52.  
  53.     Base *hoo = new Hoo;
  54.     hoo->func1();  // output once
  55. }
Success #stdin #stdout 0.01s 2860KB
comments (?)
stdin 
Standard input is empty
stdout 
Derived1
Derived2
---------
Derived2
Derived3
---------
Derived1
https://ideone.com/biPR0
language:
C++ (gcc 8.3)
created:
13 years ago
visibility:
secret

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