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  1. #include <iostream>
  2. #include <functional>
  3. #include <map>
  4. #include <typeinfo>
  5. #include <memory>
  6. using namespace std;
  7.  
  8. struct IAnimal;
  9. struct AnimalFactory
  10. {
  11.     using FactoryFunction = std::function<IAnimal*(std::string)>;
  12.     bool RegisterFunction(std::string name, FactoryFunction f)
  13.     {
  14.         factoryMap.insert(std::make_pair(name,f));
  15.         return true;
  16.     }
  17.     std::unique_ptr<IAnimal> CreateAnimal(std::string name, std::string xml)
  18.     {
  19.         return std::unique_ptr<IAnimal>(factoryMap.at(name)(xml));
  20.     }
  21.     static AnimalFactory &instance()
  22.     {
  23.         static AnimalFactory factory{};
  24.         return factory;
  25.     }
  26.  
  27. private:
  28.     std::map<std::string, FactoryFunction> factoryMap;
  29.  
  30. };
  31.  
  32. struct IAnimal{virtual ~IAnimal(){}};
  33.  
  34. struct Cat : IAnimal
  35. {
  36.     Cat (std::string xml) {}
  37.     static Cat* CreateAnimal(std::string xml) { return new Cat(xml); }
  38.     static bool registered;
  39. };
  40. bool Cat::registered = AnimalFactory::instance().RegisterFunction("cat", Cat::CreateAnimal);
  41.  
  42. struct Elephant : IAnimal
  43. {
  44.     Elephant (std::string xml) {}
  45.     static Elephant* CreateAnimal(std::string xml) { return new Elephant(xml); }
  46.     static bool registered;
  47. };
  48. bool Elephant::registered = AnimalFactory::instance().RegisterFunction("elephant", Elephant::CreateAnimal);
  49.  
  50.  
  51.  
  52. int main()
  53. {
  54.     auto cat = AnimalFactory::instance().CreateAnimal("cat","hi");
  55.     auto elephant = AnimalFactory::instance().CreateAnimal("elephant","hi");
  56.  
  57.     std::cout << typeid(*cat).name() << std::endl;
  58.     std::cout << typeid(*elephant).name() << std::endl;
  59. }
  60.  
Success #stdin #stdout 0s 3280KB
comments (?)
stdin 
Standard input is empty
stdout 
3Cat
8Elephant
https://ideone.com/SR3eKD
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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