C++设计模式Visitor+Iterator简单实现

#include<stdio.h>#include<string.h>#include<ctype.h>class ElementA;class CompositeElement;template<class T>class MyList;template<class T>class MyListIterator;template<class T>class MyList{    public:        MyList():m_size_(0), m_member_(new T*[1024]){        }        long size() const{            return m_size_;        }        void push_back(T elem){            m_member_[(++m_size_) - 1] = new T(elem);        }        T &Get(long index) const{            return *m_member_[index];        }    private:        long m_size_;        T **m_member_;};template<class T>class MyListIterator{    public:        MyListIterator(const MyList<T>* aList);        virtual void First();        virtual void Next();        virtual bool IsDone() const;        virtual T CurrentItem() const;    private:        const MyList<T>* _list;        long _current;};template<class T>MyListIterator<T>::MyListIterator(const MyList<T> *aList):_list(aList), _current(0){}template<class T>void MyListIterator<T>::First(){    _current = 0;}template<class T>void MyListIterator<T>::Next(){    _current ++;}template<class T>bool MyListIterator<T>::IsDone() const{    return _current >= _list->size();}template<class T>T MyListIterator<T>::CurrentItem() const{    if(IsDone()){        throw 20;    }    return _list->Get(_current);}const static long DEFAULT_SIZE = 10;class Visitor{    public:        virtual void VisitElementA(ElementA*){}        virtual void VisitCompositeElement(CompositeElement*){}    protected:        Visitor(){        }};class Element{    public:        virtual ~Element(){        }        virtual void Accept(Visitor&) = 0;    protected:        Element(){        }};class ElementA : public Element{    public:        ElementA(char* name):m_name_(name){                 }        virtual void Accept(Visitor& v){ v.VisitElementA(this); }        char* getName() const{            return m_name_;        }        void changeCase(){            for(int i=0; i<strlen(m_name_); i++){                m_name_[i] = toupper(m_name_[i]);            }        }    private:        char *m_name_;};class CompositeElement : public Element {    public:        CompositeElement(MyList<Element*>* list):_children(list){}        virtual void Accept(Visitor& v);    private:        MyList<Element *>* _children;};void CompositeElement::Accept(Visitor& v){    MyListIterator<Element*> iter(_children);    for(iter.First(); !iter.IsDone(); iter.Next())    {        iter.CurrentItem()->Accept(v);    }    v.VisitCompositeElement(this);}class PrintVisitor : public Visitor{    public:        virtual void VisitElementA(ElementA* elem){            printf("%s\n",elem->getName());        }};class UpperCaseVisitor : public Visitor{    public:        virtual void VisitElementA(ElementA* elem){            elem->changeCase();        }};int main(){    char *str = new char[128];    char *str2 = new char[128];    strcpy(str,"owen");    strcpy(str2,"GBS");    ElementA *newa = new ElementA(str);    ElementA *newb = new ElementA(str2);    MyList<Element*> *list = new MyList<Element*>;    list->push_back(newa);    list->push_back(newb);    CompositeElement* aptr = new CompositeElement(list);    PrintVisitor printptr;    aptr->Accept(printptr);}