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  1. #include <iostream>
  2. #include <memory>
  3.  
  4. class AbstractBase {
  5. public:
  6.     virtual void foo() = 0;
  7.     virtual ~AbstractBase() = default;
  8. };
  9.  
  10. class A : public AbstractBase {
  11. public:
  12.     void foo() override { std::cout << "Class A: foo() called" << std::endl; }
  13. };
  14.  
  15. class B : public AbstractBase {
  16. public:
  17.     void foo() override { std::cout << "Class B: foo() called" << std::endl; }
  18. };
  19.  
  20. class FooDecorator : public AbstractBase {
  21. public:
  22.     FooDecorator(AbstractBase *pBase): mpBase(pBase) { }
  23.     void foo() override
  24.     {
  25.         mpBase->foo();
  26.         ++mNumberOfFooCalls;
  27.     }
  28.     static int getFooCalls() { return mNumberOfFooCalls; }
  29.  
  30. private:
  31.     static int mNumberOfFooCalls;
  32.     AbstractBase *mpBase;
  33. };
  34.  
  35. class AbstractFactory {
  36. public:
  37.     virtual std::unique_ptr<AbstractBase> createA() = 0;
  38.     virtual std::unique_ptr<AbstractBase> createB() = 0;
  39.     virtual ~AbstractFactory() = default;
  40. };
  41.  
  42. class CountingFactory : public AbstractFactory {
  43. public:
  44.     std::unique_ptr<AbstractBase> createA()
  45.     {
  46.         // auto pA = new A();
  47.         // return std::unique_ptr<AbstractBase>(new FooDecorator(pA));
  48.         std::unique_ptr<AbstractBase> pA(new A());
  49.         return std::unique_ptr<AbstractBase>(new FooDecorator(pA.release()));
  50.     }
  51.  
  52.     std::unique_ptr<AbstractBase> createB()
  53.     {
  54.         // auto pB = new B();
  55.         // return std::unique_ptr<AbstractBase>(new FooDecorator(pB));
  56.         std::unique_ptr<AbstractBase> pB(new B());
  57.         return std::unique_ptr<AbstractBase>(new FooDecorator(pB.release()));
  58.     }
  59. };
  60.  
  61. int FooDecorator::mNumberOfFooCalls = 0;
  62.  
  63. int main()
  64. {
  65.     std::unique_ptr<AbstractFactory> pFactory(new CountingFactory());
  66.     std::unique_ptr<AbstractBase> pObjA = pFactory->createA();
  67.     std::unique_ptr<AbstractBase> pObjB = pFactory->createB();
  68.     pObjA->foo();
  69.     pObjB->foo();
  70.     std::cout << "Foo called " << FooDecorator::getFooCalls()
  71.               << " times." << std::endl;
  72. }
Success #stdin #stdout 0s 3276KB
comments (?)
stdin
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Standard input is empty
stdout
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Class A: foo() called
Class B: foo() called
Foo called 2 times.
https://ideone.com/rqpA27
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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