策略模式

#ifndef DUCK_H
#define DUCK_H

#include "FlyBehavior.h"
#include "QuackBehavior.h"

class Duck
{
public:
    void swim();
    virtual void display() = 0 ;
    void performFly()
    {
        flyBehavior->fly();
    }
    void performQuack()
    {
        quackBehavior->quack();
    }
    void setFlyBehavior(FlyBehavior* fly)
    {
        flyBehavior = fly;
    }
    void setQuackBehavior(QuackBehavior* quack)
    {
        quackBehavior = quack;
    }
public:
    FlyBehavior* flyBehavior;
    QuackBehavior* quackBehavior;
};

#endifDuck.h

#ifndef MALLARDDUCK_H
#define MALLARDDUCK_H

#include "Duck.h"
#include "FlyBehavior.h"
#include "FlyWithWings.h"
#include "Quack.h"
#include "QuackBehavior.h"
#include <iostream>

class MallardDuck : public Duck
{
public:
    MallardDuck()
    {
        flyBehavior = new FlyWithWings;
        quackBehavior = new Quack;
    }
    virtual void display()
    {
        std::cout<<"I‘m mallard duck!"<<std::endl;
    }
};

#endif

#ifndef REDHEADDUCK_H
#define REDHEADDUCK_H

#include "Duck.h"
#include "Squeak.h"
#include "FlyWithWings.h"
#include <iostream>

class RedheadDuck : public Duck
{
public:
    RedheadDuck()
    {
        quackBehavior = new Squeak;
        flyBehavior = new FlyWithWings;
    }
    virtual display()
    {
        std::cout<<"I‘m red head duck!"<<std::endl;
    }
}

#endif

#ifndef QUACKBEHAVIOR_H
#define QUACKBEHAVIOR_H

class QuackBehavior
{
public:
    virtual void quack() = 0;
};

#endif

#ifndef QUACK_H
#define QUACK_H

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

class Quack : public QuackBehavior
{
public:
    void quack()
    {
        std::cout<<"guagua jiao!"<<std::endl;
    }
};

#endif

#ifndef SQUEAK_H
#define SQUEAK_H 

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

class Squeak : public QuackBehavior
{
public:
    void quack()
    {
        std::cout<<"zhizhi jiao!"<<std::endl;
    }
};

#endif

#ifndef MUTEQUACK_H
#define MUTEQUACK_H

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

class MuteQuack : public QuackBehavior
{
public:
    void quack()
    {
        std::cout<<"buhui jiao!"<<std::endl;
    }
};

#endif

#ifndef FLYBEHAVIOR_H
#define FLYBEHAVIOR_H

class FlyBehavior
{
public:
    virtual void fly() = 0;
};

#endif

#ifndef FLYNOWAY_H
#define FLYNOWAY_H

#include "FlyBehavior.h"

#include <iostream>

class FlyNoWay : public FlyBehavior
{
public:
    void fly()
    {
        std::cout<<"Fly no way!"<<std::endl;
    }
};

#endif

#ifndef FLYWITHWINGS_H
#define FLYWITHWINGS_H

#include "FlyBehavior.h"

#include <iostream>

class FlyWithWings : public FlyBehavior
{
public:
    void fly()
    {
        std::cout<<"Fly with wings!"<<std::endl;
    }
};

#endif

#include "MallardDuck.h"
#include "Duck.h"
#include "FlyNoWay.h"

int main()
{
    Duck* md = new MallardDuck();
    md->performFly();
    md->setFlyBehavior(new FlyNoWay);
    md->performFly();
    return 1;
}