Iterator模式(C++迭代器模式)，iterator模式

Iterator模式(C++迭代器模式)，iterator模式

基本上來說，Iterator模式並沒有什麼可多說得，在STL中見得實在太多了，一般用於遍曆資料結構，其實現也相對簡單。

 

 代碼如下:

//////////////////////////////////////////////////////////////////////////// author: Jeson Yang//date:2014.12.10//file:main.cpp//////////////////////////////////////////////////////////////////////////#include <iostream>using namespace std;class Interator;class Aggregate{public:virtual ~Aggregate(){}virtual Interator* CreateItrator()=0{};virtual int GetSize()=0{}virtual int GetItem(int index)=0{}protected:Aggregate(){}};class ConcreteAggregate:public Aggregate{public:enum{size=3};ConcreteAggregate(){for(int i=0;i < size;i++)m_obj[i]=i;}~ConcreteAggregate(){}Interator* CreateItrator();int GetItem(int index){if(GetSize()) return m_obj[index];else return -1;}int GetSize(){return size;}private:int m_obj[size];};class Interator{public:virtual ~Interator(){};virtual void First()=0;virtual void Next()=0;virtual bool IsDone()=0;virtual int CurrentItem()=0;protected:Interator(){}};class ConcreteInterator:public Interator{public:ConcreteInterator(Aggregate* ag,int index=0){m_ag=ag;m_index=index;}~ConcreteInterator(){}void First(){m_index=0;}void Next(){if(m_index != m_ag->GetSize()) m_index++;}bool IsDone(){return(m_index==m_ag->GetSize());}int CurrentItem(){return m_ag->GetItem(m_index);}private:Aggregate* m_ag;int m_index;};Interator* ConcreteAggregate::CreateItrator(){return new ConcreteInterator(this);}void main(){Aggregate* ag=new ConcreteAggregate();Interator* it=new ConcreteInterator(ag);for(;!(it->IsDone());it->Next()){cout<<it->CurrentItem()<<endl;}delete it;delete ag;}