Design Pattern 设计模式1 - Strategy 1

实现 ： Defferent Heros attack Defferently. - 不同的英雄使用不用的招数

Strategy设计的思路：

基类A。更加小的基类B，新的继承类C：

1 从基类A中抽出一个更加小的基类B

2 利用这个更加小的基类B实现不同的效果

3 把这个更加小的基类B包括进基类A中去

4 新的继承类C仅仅须要和基类A打交道，设计不同行为，不须要理会更加小的基类B

#pragma once
#ifndef _STRATEGY_HEROS_H
#define _STRATEGY_HEROS_H

#include <stdio.h>

//Interface
class HeroAttack
{
public:
virtual void attack() = 0;
};

//Base method class
class Laser : public HeroAttack
{
public:
void attack()
{
puts("Super Eye-Laser");
}
};

class Smash : public HeroAttack
{
public:
void attack()
{
puts("I smash!");
}
};

class WebWebWeb : public HeroAttack
{
public:
void attack()
{
puts("Web, Web, Web!");
}
};

//Base Class
class Hero_From_Marvel
{
HeroAttack *heroAtt;
protected:
void setAttackWay(HeroAttack *hat)
{
if (heroAtt) delete heroAtt;
heroAtt = hat;
}
public:
Hero_From_Marvel() : heroAtt(nullptr)
{
}

virtual ~Hero_From_Marvel()
{
if (heroAtt) delete heroAtt;
heroAtt = nullptr;
}

void attack()
{
heroAtt->attack();
}
};

//derived class
class SuperMan : public Hero_From_Marvel
{
public:
SuperMan()
{
setAttackWay(new Laser);//这里不能使用malloc,否则内存冲突
}
};

class Hulk : public Hero_From_Marvel
{
public:
Hulk()
{
setAttackWay(new Smash);
}
};

class SpiderMan : public Hero_From_Marvel
{
public:
SpiderMan()
{
setAttackWay(new WebWebWeb);
}
};

int StrategyHerosRun()
{
const int HEROS = 3;
Hero_From_Marvel *hfm[HEROS] = {new SuperMan, new Hulk, new SpiderMan};
for (int i = 0; i < HEROS; i++)
{
hfm[i]->attack();
delete hfm[i];
}
return 0;
}

#endif