reverse_iterator的封装

2012-02-29 04:17:15 206 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

C++进阶——反向迭代器Reverse_iterator 之前我们学过适配器，但是只实现了普通的迭代器，可是反向迭代器没有实现，当时说之后会实现的，没错就是今日，我们要收复Reverse_iterator-----。我们其实可以封装一个反向迭代器库（Reverse_iterator.h），这样不管是什么容器（适配器）都可以使用了，减少了代码的冗余。阅读详情

各位好，目前我在写一个容器，其中为了能够兼容stl里面的一些东西，于是封装了自己的iterator代码，如下：



//cyclequeue的迭代器

template<class _Tp, class _Ref, class _Ptr>

struct CCycleQueue_iterator

{

    typedef random_access_iterator_tag iterator_category;

    typedef _Tp value_type;

    typedef ptrdiff_t                  difference_type;

    typedef _Ptr pointer;

    typedef _Ref reference;



    typedef CCycleQueue_iterator<_Tp,_Tp&,_Tp*>             iterator;

    typedef CCycleQueue_iterator<_Tp,const _Tp&,const _Tp*> const_iterator;

    typedef CCycleQueue_iterator<_Tp,_Ref,_Ptr>             _Self;

    typedef size_t                     size_type;

    typedef CCycleQueue<_Tp> _Cyclequeue;



    _Cyclequeue* m_pCycleQueue;

    size_type m_unPos;



    CCycleQueue_iterator(_Cyclequeue* x, size_type __pos) : m_pCycleQueue(x),m_unPos(__pos) {}

    CCycleQueue_iterator() {}

    CCycleQueue_iterator(const iterator& x):m_pCycleQueue(x.m_pCycleQueue),m_unPos(x.m_unPos) {}



    reference operator*() const

    {

        return (*m_pCycleQueue)[m_unPos];

    }



    pointer operator->() const

    {

        return &(operator*());

    }



    bool operator==(const CCycleQueue_iterator& x) const

    {

        return ((m_pCycleQueue == x.m_pCycleQueue) && (m_unPos == x.m_unPos));

    }



    bool operator!=(const CCycleQueue_iterator& x) const

    {

        return ((m_pCycleQueue != x.m_pCycleQueue) || (m_unPos != x.m_unPos));

    }



    _Self& operator++()

    {

        m_unPos++;

        return *this;

    }



     _Self& operator+(const size_type& __size)

    {

        m_unPos += __size;

        return *this;

    }



    _Self operator++(int)

    {

        _Self __tmp = *this;

        m_unPos++;

        return __tmp;

    }

    _Self& operator--()

    {

        m_unPos--;

        return *this;

    }

    _Self operator--(int)

    {

        _Self __tmp = *this;

        m_unPos--;

        return __tmp;

    }

};

我在容器类中使用反向迭代器的时候的时候，出现该错误，不知何解，还请高手请教：



template <typename _Tp>

class CCycleQueue

{

public:

    typedef _Tp value_type;

    typedef value_type* pointer;

    typedef const value_type* const_pointer;

    typedef CCycleQueue_iterator<_Tp, _Tp&, _Tp*> iterator;

    typedef const CCycleQueue_iterator<_Tp, const _Tp&, const _Tp*> const_iterator;

    typedef reverse_iterator<const_iterator> const_reverse_iterator;

    typedef reverse_iterator<iterator>       reverse_iterator;

    typedef value_type& reference;

    typedef const value_type& const_reference;

    typedef size_t size_type;





使用函数：

 inline reverse_iterator rbegin()

    {

        return  reverse_iterator(end());

    }



    inline reverse_iterator rend()

    {

        return reverse_iterator(begin());

    }



错误：

||=== test, Debug ===|

D:\project\Test\cyclequeue.h|97|error: declaration of 'typedef class std::reverse_iterator<CCycleQueue_iterator<_Tp, _Tp&, _Tp*> > CCycleQueue<_Tp>::reverse_iterator'|



d:\green\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.4.1\include\c++\bits\stl_iterator.h|96|error: changes meaning of 'reverse_iterator' from 'class std::reverse_iterator<CCycleQueue_iterator<_Tp, _Tp&, _Tp*> >'|

||=== Build finished: 2 errors, 0 warnings (0 minutes, 0 seconds) ===|