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  1. #include <iostream>
  2. #include <vector>
  3.  
  4. class Base;
  5. class Derived1;
  6. class Derived2;
  7.  
  8. class IBaseVisitor
  9. {
  10. public:
  11.     virtual ~IBaseVisitor() = default;
  12.     virtual void visit(Base&) = 0;
  13.     virtual void visit(Derived1&) = 0;
  14.     virtual void visit(Derived2&) = 0;
  15. };
  16.  
  17. class Base
  18. {
  19. public:
  20.     Base() { std::cout << "Base::Base" << std::endl; }
  21.     virtual ~Base() { std::cout << "Base::~Base" << std::endl; }
  22.     virtual void accept(IBaseVisitor& v) { v.visit(*this); }
  23. };
  24.  
  25. class Derived1 : public Base
  26. {
  27. public:
  28.     void func1() { std::cout << "Derived1::func1()" << std::endl; }
  29.     void accept(IBaseVisitor& v) override { v.visit(*this); }
  30. };
  31.  
  32. class Derived2 : public Base
  33. {
  34. public:
  35.     void func2() { std::cout << "Derived2::func2()" << std::endl; }
  36.     void accept(IBaseVisitor& v) override { v.visit(*this); }
  37. };
  38.  
  39.  
  40. struct SomeFuncVisitor : IBaseVisitor
  41. {
  42.     void visit(Base&) override { std::cout << "None" << std::endl; }
  43.     void visit(Derived1& d1) override { d1.func1(); }
  44.     void visit(Derived2& d2) override { d2.func2(); }
  45. };
  46.  
  47. int main()
  48. {
  49.     Derived1 derived1;
  50.     Derived2 derived2;
  51.     std::vector<Base *> vb {&derived1, &derived2};
  52.  
  53.     SomeFuncVisitor visitor;
  54.     for (Base* base : vb) {
  55.         base->accept(visitor);
  56.     }
  57. }
  58.  
Success #stdin #stdout 0s 16064KB
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stdin
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Standard input is empty
stdout
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Base::Base
Base::Base
Derived1::func1()
Derived2::func2()
Base::~Base
Base::~Base
https://ideone.com/1BezgT
language:
C++ (gcc 8.3)
created:
8 years ago
visibility:
public

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