c++设计模式之状态模式

状态模式思想：定义一个状态类，里面可以实现多种状态的转换，每个状态由一个单独类来判断和实现，对象里有设置更新状态的方法，获得当前状态的方法来跳转到其他状态类的方法中（因为setstate的时候把state的状态变为另一个子类，然后调用子类自己的判断方法，满足条件，则用new一个新状态代替原来状态来跳转－>使用对象的getstate，此时调用的“当前状态函数”是new出来状态的对象的（即父类的子类方法实现接管- -））  总结：状态方法判断，达到条件，对象执行set新状态方法，对象get到新状态的Currentstate然后转到新状态自己判断方法中！#include <iostream>#include <string>#include <vector>

using namespace std;class War;class State{public:    virtual void Prophase() {}    virtual void Metaphase() {}    virtual void Anaphase() {}    virtual void End() {}    virtual void CurrentState(War *war) {}};//战争class War{private:    State *m_state;  //目前状态    int m_days;      //战争持续时间public:    War(State *state)            : m_state(state),              m_days(0)    {}    ~War()    {        delete m_state;    }    int GetDays()    {        return m_days;    }    void SetDays(int days)    {        m_days = days;    }    void SetState(State *state)    {        delete m_state; m_state = state;    }    void GetState()    {        m_state->CurrentState(this);    }};

//战争结束class EndState: public State{public:    void End(War *war) //结束阶段的具体行为    {        cout<<"战争结束"<<endl;    }    void CurrentState(War *war) { End(war); }};//后期class AnaphaseState: public State{public:    void Anaphase(War *war) //后期的具体行为    {        if(war->GetDays() < 30)            cout<<"第"<<war->GetDays()<<"天：战争后期，双方拼死一搏"<<endl;        else        {            war->SetState(new EndState());            war->GetState();        }    }    void CurrentState(War *war) { Anaphase(war); }};//中期class MetaphaseState: public State{public:    void Metaphase(War *war) //中期的具体行为    {        if(war->GetDays() < 20)            cout<<"第"<<war->GetDays()<<"天：战争中期，进入相持阶段，双发各有损耗"<<endl;        else        {            war->SetState(new AnaphaseState());            war->GetState();        }    }    void CurrentState(War *war) { Metaphase(war); }};//前期class ProphaseState: public State{public:    void Prophase(War *war)  //前期的具体行为    {        if(war->GetDays() < 10)            cout<<"第"<<war->GetDays()<<"天：战争初期，双方你来我往，互相试探对方"<<endl;        else        {            war->SetState(new MetaphaseState());            war->GetState();        }    }    void CurrentState(War *war) { Prophase(war); }};

int main(){    War *war = new War(new ProphaseState());    for(int i = 1; i < 40;i += 5)    {        war->SetDays(i);        war->GetState();    }    delete war;    return 0;}