第十六章-状态模式

基本代码

#include<iostream>
#include<string>
#include<vector>

using namespace std;

class Context;

class State
{
public:
    virtual void Handle(Context* context) = 0;
};

//Context类，维护一个ConcreteState子类的实例，这个实例定义当前的状态
class Context
{
private:
    State* state;
public:
    Context(State* state_t) { state = state_t; } //定义Context的初始状态

    State* get() { return state; }
    void set(State* state_t) { state = state_t; }

    void Request()   //对请求做处理，并设置下一个状态
    {
        state->Handle(this);
    }
};

class ConcreteStateA : public State
{
public:
    ConcreteStateA();
    void Handle(Context* context);   //设置ConcreteStateA的下一个状态，具体实现要写在累外面，避免顺序问题
};

class ConcreteStateB : public State
{
public:
    void Handle(Context* context)
    {
        cout << "B" << endl;
        context->set(new ConcreteStateA());
    }
};

ConcreteStateA::ConcreteStateA() {}
void ConcreteStateA:: Handle(Context* context)
{
    cout << "A" << endl;
    context->set(new ConcreteStateB());
}



int main()
{
    Context* c = new Context(new ConcreteStateA());

    c->Request();
    c->Request();
    c->Request();
    c->Request();

    system("pause");
    return 0;
}

工作状态-状态模式版

//work.h

class Work;

//抽象状态
class State
{
public:
    virtual void WriteProgram(Work* w) = 0;
};

//上午工作状态类
class ForenoonState :public State
{
    void WriteProgram(Work* w);
};

//中午工作状态类
class NoonState :public State
{
    void WriteProgram(Work* w);
};

//下午工作状态类
class AfternoonState :public State
{
    void WriteProgram(Work* w);
};

//晚间工作状态类
class EveningState :public State
{
    void WriteProgram(Work* w);
};

//睡眠状态类
class SleepingState :public State
{
    void WriteProgram(Work* w);
};

//下班休息类
class RestState :public State
{
    void WriteProgram(Work* w);
};

//工作类
class Work
{
private:
    State* current;
    double hour;
    bool finish;
public:
    Work()
        : current(new ForenoonState()), hour(0), finish(true) {}

    double getHour() { return hour; }
    void setHour(double hour_t) { hour = hour_t; }
    bool getTaskFinish() { return finish; }
    void setTaskFinish(bool finish_t) { finish = finish_t; }
    void setState(State* s) { current = s; }

    void WriteProgram()
    {
        current->WriteProgram(this);
    }
};

//work.cpp

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

void ForenoonState::WriteProgram(Work* w)
{
    if (w->getHour() < 12)
    {
        std::cout << "当前时间：" << w->getHour() << "点 " << "上午工作，精神百倍。" << std::endl;;
    }
    else
    {
        w->setState(new NoonState());
        w->WriteProgram();
    }
}

void NoonState::WriteProgram(Work* w)
{
    if (w->getHour() < 13)
    {
        std::cout << "当前时间：" << w->getHour() << "点 " << "饿了，午饭：犯困，午休。" << std::endl;;
    }
    else
    {
        w->setState(new AfternoonState());
        w->WriteProgram();
    }
}

void AfternoonState::WriteProgram(Work* w)
{
    if (w->getHour() < 17)
    {
        std::cout << "当前时间：" << w->getHour() << "点 " << "下午状态还不错，继续努力。" << std::endl;;
    }
    else
    {
        w->setState(new EveningState());
        w->WriteProgram();
    }
}

void EveningState::WriteProgram(Work* w)
{
    if (w->getTaskFinish())
    {
        w->setState(new RestState());
        w->WriteProgram();
    }
    else
    {
        if (w->getHour() < 21)
        {
            std::cout << "当前时间：" << w->getHour() << "点 " << "加班哦，疲劳之极。" << std::endl;;
        }
        else
        {
            w->setState(new SleepingState());
            w->WriteProgram();
        }
    }
}

void SleepingState::WriteProgram(Work* w)
{

    std::cout << "当前时间：" << w->getHour() << "点 " << "不行了，睡着了。" << std::endl;;
}

void RestState::WriteProgram(Work* w)
{

    std::cout << "当前时间：" << w->getHour() << "点 " << "下班回家了。" << std::endl;;
}

//main.cpp

#include<iostream>
#include<string>
#include<vector>
#include"work.h"

using namespace std;

int main()
{
    Work* emergencyProjects = new Work();
    emergencyProjects->setHour(9);
    emergencyProjects->WriteProgram();
    emergencyProjects->setHour(10);
    emergencyProjects->WriteProgram();
    emergencyProjects->setHour(12);
    emergencyProjects->WriteProgram();
    emergencyProjects->setHour(13);
    emergencyProjects->WriteProgram();
    emergencyProjects->setHour(14);
    emergencyProjects->WriteProgram();
    emergencyProjects->setHour(17);

    emergencyProjects->setTaskFinish(false);

    emergencyProjects->WriteProgram();
    emergencyProjects->setHour(19);
    emergencyProjects->WriteProgram();
    emergencyProjects->setHour(22);
    emergencyProjects->WriteProgram();



    system("pause");
    return 0;
}