实例解析C++设计模式编程中简单工厂模式的采用

举个例子：有一家生产处理器核的厂家，它只有一个工厂，能够生产两种型号的处理器核。客户需要什么样的处理器核，一定要显示地告诉生产工厂。
下面给出一种实现方案。

#include <iostream>
using namespace std;

enum CoreType
{
 CORE_A,
 CORE_B
};

class SingleCore
{
public:
 virtual void Show() = 0;
};

/*
 * A 型号单核
 */
class SingleCoreA: public SingleCore
{
public:
 void Show()
 {
 cout<<"show SingleCoreA"<<endl;
 }
};

/*
 * B 型号单核
 */
class SingleCoreB: public SingleCore
{
public:
 void Show()
 {
 cout<<"show SingleCoreB"<<endl;
 }
};

/*
 * 唯一的工厂，可以生产单核 两种型号的处理器
 */ 
class Factory
{
public:
 SingleCore* CreateSingleCore(CoreType ctype)
 {
 switch(ctype) 
 {
 case CORE_A:
 return new SingleCoreA();

 case CORE_B:
 return new SingleCoreB();
 
 default:
 return NULL;
 }
 }
};


int main()
{
 Factory   *pstFactory;
 SingleCore *pstSingleCore;
 
 pstFactory  = new Factory();

 /*
 * 生产A核
 */
 pstSingleCore = pstFactory->CreateSingleCore(CORE_A);
 pstSingleCore->Show();

 system("pause");

 /*
 * 生产B核
 */
 pstSingleCore = pstFactory->CreateSingleCore(CORE_B);
 pstSingleCore->Show();

 /*
 * 生产A核
 */
 pstSingleCore = pstFactory->CreateSingleCore(CORE_A);
 pstSingleCore->Show();

 /*
 * 生产A核
 */
 pstSingleCore->Show();

 system("pause");

 /*
 * 生产B核
 */
 pstSingleCore = pstFactory->CreateSingleCore(CORE_B);
 pstSingleCore->Show();
 
 return 0;
}

show SingleCoreA
请按任意键继续. . .
show SingleCoreB
show SingleCoreA
show SingleCoreA
请按任意键继续. . .
show SingleCoreB
Press any key to continue