[C++] c++设计模式——工厂模式

#include <iostream>
using namespace std;
class Product
{
public:
  virtual void show()=0;
};
class PA:public Product
{
public:
  void show()
  {
    cout<<"this is a"<<endl;
    return ;
  }
};
class PB:public Product
{
public:
  void show()
  {
    cout<<"this is b"<<endl;
    return ;
  }
};
class Factroy
{
public:
  Product* create(int i)
  {
    switch (i)
    {
    case 1:
      return new PA();
      break;
    case 2:
      return new PB();
      break;
    default:
      return nullptr;
    }
    return nullptr;
  }
};
int main()
{
  
  Factroy f;
  f.create(1)->show();
  f.create(2)->show();
  return 0;
}

#include <iostream>
using namespace std;
class Product
{
public:
  virtual void show()=0;
};
class PA:public Product
{
public:
  void show()
  {
    cout<<"this is a"<<endl;
    return ;
  }
};
class PB:public Product
{
public:
  void show()
  {
    cout<<"this is b"<<endl;
    return ;
  }
};
class Factroy
{
public:
  virtual Product* create()=0;
};
class FA:public Factroy
{
public:
  Product* create()
  {
    return new PA();
  }
};
class FB:public Factroy
{
public:
  Product* create()
  {
    return new PB();
  }
};
int main()
{
  FA fa;
  fa.create()->show();
  FB fb;
  fb.create()->show();
  return 0;
}