Iterator mode (C ++ iterator mode) and Iterator Mode

Iterator mode (C ++ iterator mode) and Iterator Mode

Basically speaking, the Iterator mode is nothing to say, and there are too many ideas in STL. It is generally used to traverse data structures and its implementation is relatively simple.

 

The Code is as follows:

//////////////////////////////////////////////////////////////////////////// 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;}