设计模式[8]-Iterator

Type: Behavioral

Iterator：提供一个方法连续访问一个聚合对象的元素，同时不暴露其底层表示

#include iostream 

using namespace std; 

#define Data int 

class Iterator 

public: 

 virtual Data* next()=0; 

class ConcreteIterator: public Iterator 

public: 

 ConcreteIterator(Data* data, int* size) 

 m_pData = data; 

 m_pSize = size; 

 mIndex = 0; 

 Data* next() 

 if(m_pData != NULL mIndex *m_pSize){ 

 return m_pData[mIndex++]; 

 } else { 

 return NULL; 

private: 

 int mIndex; 

 Data* m_pData; 

 int* m_pSize; 

class Aggregate 

public: 

 virtual Iterator* createIterator() = 0; 

class ConcreteAggregate: public Aggregate 

public: 

 ConcreteAggregate(int size) 

 mSize = size; 

 mData = new Data[size]; 

 for(int i=0;i size; i++) 

 mData[i] = i; 

 Iterator* createIterator() 

 Iterator* iterator = new ConcreteIterator(this- mData, this- mSize); 

 return iterator; 

private: 

 Data* mData; 

 int mSize; 

int main() 

 Aggregate* pAggregate = new ConcreteAggregate(4); 

 Iterator* pIterator = pAggregate- createIterator(); 

 Data* data; 

 int count = 0; 

 while (data = pIterator- next()) 

 if(count ++ 10) 

 break; 

 cout *data endl; 

 system("pause"); 

 return 0;