#include <iostream>
using namespace std;
class Work;

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

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

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

class Work {
private:
    State  * current;
    double hour;
    
    bool finish = false;
    
public:
    Work(){current = new ForenoonState(); }
    double getHour(){return  hour;}
    void setHour(double hour){this->hour = hour;
        if (hour > 10) {
            current = new NoonState();
        } else {
            current = new ForenoonState();
        }
    }
    bool getFinish(){return  finish;}
    void setFinish(bool finish){this->finish = finish;}
    State *  getState(){return  current;}
    void setState(State * state){this->current = state;}
    
    void WriteProgram(){current->WriteProgram(this);}
};

//.m
void ForenoonState::WriteProgram(Work *work) {
    cout<< "it is"<<work->getHour()<<"i want to start work"<<endl;
}

void NoonState::WriteProgram(Work *work) {
    cout<< "it is"<<work->getHour()<<"i want to finish work"<<endl;
}

    Work * emergencyProject = new Work();
    emergencyProject->setHour(5);
    emergencyProject->WriteProgram();
    emergencyProject->setHour(30);
    emergencyProject->WriteProgram();

狀態(tài)模式主要解決的是當控制一個對象狀態(tài)轉換的條件表達式過于復雜時的情況。將狀態(tài)的判斷邏輯轉移到表示不同狀態(tài)的一系列類中可以把復雜的判斷邏輯簡化。

好處就是將與特定狀態(tài)的相關行為局部化，并且將不同狀態(tài)的行為分割開來。

當一個對象的行為取決于它的狀態(tài)，并且它必須在運行時刻根據(jù)狀態(tài)改變它的行為時，就可以考慮使用狀態(tài)模式了。