reverse_iterator的封装实现

 Reverse_Iterator.h

namespace xx
{
	// 所有容器的反向迭代器
	// 迭代器适配器
	template<class Iterator, class Ref, class Ptr>
	struct Reverse_iterator
	{
		Iterator _it;
		typedef Reverse_iterator<Iterator, Ref, Ptr> Self;

		Reverse_iterator(Iterator it)
			:_it(it)
		{}

		Ref operator*()
		{
			Iterator temp(_it);
			--temp;
			return *temp;
		}

		//Ref operator*()
		//{
		//	Iterator tmp = _it;
		//	return *(--tmp);
		//}

		Ptr operator->()
		{
			return &(operator*());
		}

		Self& operator++()
		{
			--_it;
			return *this;
		}

		Self& operator--()
		{
			++_it;
			return *this;
		}

		bool operator!=(const Self& s)
		{
			return _it != s._it;
		}
	};
}

适配到vector和list中做反向迭代器

vector.h

#include"Reverse_Iterator.h"
namespace xx
{
    template<class T>
	class vector
	{
	public:
		typedef T* iterator;
		typedef const T* const_iterator;

		// 反向迭代器适配支持
		typedef Reverse_iterator<iterator, T&, T*> reverse_iterator;
		typedef Reverse_iterator<const_iterator, const T&, const T*> const_reverse_iterator;

		const_reverse_iterator rbegin() const
		{
			// list_node<int>*
			return const_reverse_iterator(end());
		}

		const_reverse_iterator rend() const
		{
			return const_reverse_iterator(begin());
		}

		reverse_iterator rbegin()
		{
			return reverse_iterator(end());
		}

		reverse_iterator rend()
		{
			return reverse_iterator(begin());
		}

		iterator begin()
		{
			return _start;
		}

		iterator end()
		{
			return _finish;
		}

		const_iterator begin() const
		{
			return _start;
		}

		const_iterator end() const
		{
			return _finish;
		}
		// ...
}

list.h

namesapce xx
{
    template<class T>
	class list
	{
		typedef list_node<T> Node;
	public:
		typedef ListIterator<T, T&, T*> iterator;
		typedef ListIterator<T, const T&, const T*> const_iterator;

		// 反向迭代器适配支持
		typedef Reverse_iterator<iterator, T&, T*> reverse_iterator;
		typedef Reverse_iterator<const_iterator, const T&, const T*> const_reverse_iterator;

		const_iterator begin() const
		{
			// list_node<int>*
			return const_iterator(_head->_next);
		}

		const_iterator end() const
		{
			return const_iterator(_head);
		}

		iterator begin()
		{
			return iterator(_head->_next);
			//return _head->_next;
		}

		iterator end()
		{
			return iterator(_head);
		}

		const_reverse_iterator rbegin() const
		{
			// list_node<int>*
			return const_reverse_iterator(end());
		}

		const_reverse_iterator rend() const
		{
			return const_reverse_iterator(begin());
		}

		reverse_iterator rbegin()
		{
			return reverse_iterator(end());
		}

		reverse_iterator rend()
		{
			return reverse_iterator(begin());
		}
        //...
    }
  }