(一)策略模式C++

main()，赵云

CContext，锦囊

IStrategy，策略接口

CBackDoor，策略之一

CGivenGreenLight，策略之二

CBlockEnemy，策略之三

说明：一个策略放到一个锦囊里。当用的时候，找到这个锦囊，从锦囊里拿出策略来使用。

注意：锦囊只是简单的装载和调用策略，锦囊里没有逻辑。策略会有更大的自主权，运行更多的逻辑

//Strategy.h

#ifndef STRATEGY_H_
#define STRATEGY_H_

class Strategy
{
public:
Strategy();
~Strategy();
virtual void Operate() = 0;
};

class BackDoor:public Strategy
{
public:
BackDoor();
~BackDoor();
void Operate();
};

class GivenGreenLight:public Strategy
{
public:
GivenGreenLight();
~GivenGreenLight();
void Operate();
};

class BlockEnemy:public Strategy
{
public:
BlockEnemy();
~BlockEnemy();
void Operate();
};

#endif//Strategy.cpp

#include "Strategy.h"
#include <iostream>

using namespace std;

Strategy::Strategy() {}
Strategy::~Strategy() {}

BackDoor::BackDoor() {}
BackDoor::~BackDoor() {}

void BackDoor::Operate()
{
cout<<"找叫人帮忙，给孙权施压"<<endl;
}

GivenGreenLight::GivenGreenLight() {}
GivenGreenLight::~GivenGreenLight() {}
void GivenGreenLight::Operate()
{
cout<<"求吴国开个绿灯，放行"<<endl;
}

BlockEnemy::BlockEnemy() {}
BlockEnemy::~BlockEnemy() {}
void BlockEnemy::Operate()
{
cout<<"孙夫人断后，阻挡追兵"<<endl;
}


//Context.h

#ifndef CONTEXT_H_
#define CONTEXT_H_

#include "Strategy.h"

class Context
{
public:
Context(Strategy *pStrategy);
~Context();
void Operate();
private:
Strategy *m_pStrategy;
};

#endif

//Context.cpp

#include "Context.h"
#include <iostream>

using namespace std;

Context::Context(Strategy *pStrategy)
{
m_pStrategy = pStrategy;
}
Context::~Context()
{
delete this->m_pStrategy;
}
void Context::Operate()
{
this->m_pStrategy->Operate();
}

//main.cpp

#include <iostream>
#include <stdlib.h>
#include "Strategy.h"
#include "Context.h"

using namespace std;

int main()
{
Context *pContext;

cout<<"------刚到吴国请拆第一个锦囊-------"<<endl;
pContext = new Context(new BackDoor());
pContext->Operate();
delete pContext;

cout<<"-----刘备不思蜀，就要拆第二个------"<<endl;
pContext = new Context(new GivenGreenLight());
pContext->Operate();
delete pContext;

cout<<"------孙权的追兵来了，就拆第三个------"<<endl;
pContext = new Context(new BlockEnemy());
pContext->Operate();
delete pContext;

return 0;
}

相对来说这个是比较好理解的例子