状态模式

#ifndef STATE_H_
#define STATE_H_
#include <cstdio>

//
class State;

class Work
{
private:
    State* state_;
    int hour_;
public:
    Work();
    ~Work();

    void SetHour(int hour);
    int GetHour();

    void SetState(State* state);
    State* GetState();

    void WriteProgram();
};


class State
{
public:
    virtual void WriteProgram(Work* work) {};
    virtual ~State(){} 
};


class ForenoonState : public State
{
public:
    void WriteProgram(Work* work);
};


class NoonState : public State
{
public:
    void WriteProgram(Work* work);
};


class AfternoonState : public State
{
public:
    void WriteProgram(Work* work);
};


class EveningState : public State
{
public:
    void WriteProgram(Work* work);
};


class SleepingState : public State
{
public:
    void WriteProgram(Work* work);
};


class RestState :public State
{
public:
    void WriteProgram(Work* work)
    {
        printf("Rest state\n");
    }
};

#endif

#include "state.h"


Work::Work()
{
    state_ = new ForenoonState();
}

Work::~Work()
{
    if (state_ != NULL)
    {
        delete state_;
    }
}

void Work::SetHour(int hour)
{
    hour_ = hour;
}

int Work::GetHour() { return hour_; }

void Work::SetState(State* state)
{
    state_ = state;
}

State* Work::GetState() { return state_; }


void Work::WriteProgram()
{
    state_->WriteProgram(this);
}


void ForenoonState::WriteProgram(Work* work)
{
    if (work->GetHour() < 12)
    {
        printf("forenoon work state\n");
    }
    else
    {
        State* sta = work->GetState();
        delete sta;
        work->SetState(new NoonState());
        work->WriteProgram();
    }
}


void NoonState::WriteProgram(Work* work)
{
    if (work->GetHour() < 13)
    {
        printf("noon work state\n");
    }
    else
    {
        State* sta = work->GetState();
        delete sta;
        work->SetState(new AfternoonState());
        work->WriteProgram();
    }
}


void AfternoonState::WriteProgram(Work* work)
{
    if (work->GetHour() < 17)
    {
        printf("AfternoonState work state\n");
    }
    else
    {
        State* sta = work->GetState();
        delete sta;
        work->SetState(new EveningState());
        work->WriteProgram();
    }
}


void EveningState::WriteProgram(Work* work)
{
    if (work->GetHour() < 21)
    {
        printf("EveningState work state\n");
    }
    else
    {
        State* sta = work->GetState();
        delete sta;
        work->SetState(new SleepingState);
        work->WriteProgram();
    }
}


void SleepingState::WriteProgram(Work* work)
{
    if (work->GetHour() < 22)
    {
        printf("Sleeping state\n");
    }
    else
    {
        State* sta = work->GetState();
        delete sta;
        work->SetState(new RestState());
        work->WriteProgram();
    }
}