设计模式（2）：工厂模式

#include <iostream>
#include <string>
using namespace std;


class Product
{   
    public:
    virtual void ShowInfo() = 0;
};

class ProductA : public Product
{
    public:
    void ShowInfo()
    {
        cout << "this is product A." << endl;
    }
};

class ProductB : public Product
{
    public:
    void ShowInfo()
    {
        cout << "this is product B." << endl;
    }
};

class Factory
{
    public:
    virtual Product* createProduct(string type) = 0;
};

class FactoryA : public Factory
{
    Product* createProduct(string type)
    {
        return new ProductA();
    }
};

class FactoryB : public Factory
{
    Product* createProduct(string type)
    {
        return new ProductB();
    }
};

int main()
{   
    Factory *facA = new FactoryA();
    Product *pA = facA->createProduct("A");
    if(pA != nullptr)
        pA->ShowInfo();
    Factory *facB = new FactoryB();
    Product *pB = facB->createProduct("B");
    if(pB != nullptr)
        pB->ShowInfo();

}