设计模式之职责链模式

1,职责链的本质:尝试多个解决方法,直到找到一个起作用的方法.
2,实例代码

#include <iostream>
#include <vector>
using namespace std;

enum Answer{ NO,YES };
class Response
{
public:
    virtual Answer canIHave()=0;
    virtual ~Response() {}
};

class AskMum : public Response
{
public:
    Answer canIHave()
    {
        cout<<"mum,can I have?"<<endl;
        return NO;
    }
};
class AskDad : public Response
{
public:
    Answer canIHave()
    {
        cout<<"dad,can I have?"<<endl;
        return NO;
    }
};
class AskUncle : public Response
{
public:
    Answer canIHave()
    {
        cout<<"uncle,can I have?"<<endl;
        return YES;
    }
};

class RunResponse : public Response
{
    vector<Response*> chain;
public:
    RunResponse()
    {
        chain.push_back(new AskMum);
        chain.push_back(new AskDad);
        chain.push_back(new AskUncle);
    }
    Answer canIHave()
    {
        vector<Response*>::iterator ite=chain.begin();
        while(ite!=chain.end())
        {
            if((*ite++)->canIHave()==YES)
                return YES;
        }
        cout<<"All NO."<<endl;
        return NO;
    }
    //记得释放堆内存
    ~ RunResponse()
    {
        vector<Response*>::iterator ite=chain.begin();
        while(ite!=chain.end())
        {
            delete *ite++;
        }
    }

};



int main()
{
    RunResponse chain;
    chain.canIHave();
    return 0;
}