【设计模式】状态模式

// State.cpp : 定义控制台应用程序的入口点。
//


#include "stdafx.h"
#include <iostream>
using namespace std;

//强制声明
class CMe;

//状态抽象基类
class CState
{
public: 
    CState();
    virtual ~CState(); 
    virtual void Show(CMe* pMe) = 0;   
};

CState::CState(){}
CState::~CState(){}


//单身状态类
class CSingle : public CState
{
public:
    CSingle();
    virtual ~CSingle();
    virtual void Show(CMe* pMe);
};

CSingle::CSingle(){}
CSingle::~CSingle(){}
void CSingle::Show(CMe* pMe)
{
    cout << endl << "哥哥是单身狗啊单身狗！！！" << endl;    
}


//有女朋友状态类
class CWithGirl : public CState
{
public:
    CWithGirl();
    virtual ~CWithGirl();
    virtual void Show(CMe* pMe) ;
};

CWithGirl::CWithGirl(){}
CWithGirl::~CWithGirl(){}
void CWithGirl::Show(CMe* pMe)
{ 
    cout << endl << "哥哥有女朋友了啊好幸福！！！" << endl;
}


//我 类
class CMe
{
public:
    CMe();
    virtual ~CMe();
    void SetState(CState* pState);  //设置状态
    void ShowMsg();                    //显示此状态的信息

protected:
    CState* m_ptrState; 
};

CMe::CMe() : m_ptrState(NULL){}
CMe::~CMe(){}
void CMe::SetState(CState* pState)
{
    m_ptrState = pState;
}
void CMe::ShowMsg()
{
    m_ptrState->Show(this);
}



int _tmain(int argc, _TCHAR* argv[])
{ 
    CMe me1;
    me1.SetState(new CSingle());
    me1.ShowMsg();

    cout << endl << endl;

    me1.SetState(new CWithGirl());
    me1.ShowMsg();

    cout << endl << endl;

    return 0;
}