工厂模式

#include <iostream>
#include <memory>

class Product {
public:
    virtual void show() const { std::cout << "In Product show()." << std::endl; }
};

class ConcreteProduct1 : public Product {
public:
    void show() const override { std::cout << "In ConcreteProduct1 show()." << std::endl; }
};

class ConcreteProduct2 : public Product {
public:
    void show() const override { std::cout << "In ConcreteProduct2 show()." << std::endl; }
};

class AbstractFactory {
public:
    virtual std::unique_ptr<Product> createProduct() = 0;
};

class ConcrateFactory1 : public AbstractFactory {
public:
    std::unique_ptr<Product> createProduct() override { return std::make_unique<ConcreteProduct1>(); }
};

class ConcrateFactory2 : public AbstractFactory {
public:
    std::unique_ptr<Product> createProduct() override { return std::make_unique<ConcreteProduct2>(); }
};


int main(int argc, char *argv[]) {
  std::unique_ptr<AbstractFactory> f = std::make_unique<ConcrateFactory1>();
  std::unique_ptr<Product> p = f->createProduct();
  p->show();
  f = std::make_unique<ConcrateFactory2>();
  p = f->createProduct();
  p->show();
  return 1;
}