#include<iostream>

using namespace std;

//前项声明

class Context;

//抽象状态类定义

class State

{

protected:

    State(){}

public:

    virtual~State() =

    {};

    void setContext(Context *x)

    {

        _context = x;

    }

    virtual void handler1() = ;

    virtual void handler2() = ;

private:

    Context *_context;

};

//具体状态定义

class ConcreteState1 :public State

{

public:

    ConcreteState1(){}

    ~ConcreteState1(){}

    void handler1()

    {

        cout << "ConcreteState1::handler1" << endl;

    }

    void handler2()

    {

        cout << "ConcreteState1::handler2" << endl;

    }

private:

};

//具体状态定义

class ConcreteState2 :public State

{

public:

    ConcreteState2(){}

    ~ConcreteState2(){}

    void handler1()

    {

        cout << "ConcreteState2::handler1" << endl;

    }

    void handler2()

    {

        cout << "ConcreteState2::handler2" << endl;

    }

private:

};

//环境类

class Context

{

public:

    Context()

    :Sta1(new ConcreteState1)

    ,Sta2(new ConcreteState2)

    {}

    State* getCurrentState()

    {

        return CurrentState;

    }

    void SetCurrentState(State* s)

    {

        CurrentState = s;

        CurrentState->setContext(this);

    }

    void handler1()

    {

        CurrentState->handler1();

    }

    void handler2()

    {

        CurrentState->handler2();

    }

    ~Context(){}

private:

    //当前状态则是所有状态中的一种

    State *CurrentState;

    //所有状态应当定义为static比较合适

    State *Sta1;

    State *Sta2;

};

void TestState()

{

    Context * context = new Context();

    context->SetCurrentState(new ConcreteState1());

    context->handler1();

    context->handler2();

    context->SetCurrentState(new ConcreteState2());

    context->handler1();

    context->handler2();

}