软件设计模式 --状态模式_软件设计中多种状态变量

//P: 抽象状态类，实现具体类，根据需要生成具体类对象赋值给抽象类变量 

强调的是对象，不同情况下，自生状态的改变

2021.08.3： 强调状态的变化， 所以把状态 抽象出来。

#include <stdio.h>
#include   <iostream>   
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); }  
}; 
 
 
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 *m_war =  new War(new ProphaseState);
 
	for (int i=0 ;i< 40; i=i+10)
	{
		m_war->SetDays(i);
		m_war->GetState();
	}
	delete m_war;
	getchar();
	return 0;
}