20120918LIST类定义《数据结构与算法分析》

LIST类结构

template <typename Object>
class List
{
    private:
        struct Node//所有都是公有的
        {
            Object data;
            Node *prev;
            Node *next;

            Node(const Object & d = Object(),Node *p = NUll，Node *n = Null):
            data(d) , prev(p) , next(n)
            {
            }
        };
    public:
        class const_iterator
        {
                public:
                    const_iterator() : current(NULL){}
                    const Object & operator* () const
                    {
                        return retrieve();
                    }
                    const_iterator & operator++ ( ) const
                    {
                        current = current->next;
                        return *this;
                    }
                    const_iterator & operator++( int )
                    {
                        const_iterator old = *this;
                        ++(*this);
                        return old;
                    }
                    bool operator == (const const_iterator * rhs) const
                    {
                        return current == rhs.current;
                    }
                    bool operator != (const const_iterator & rhs) const
                    {
                        return !(*this == rhs);
                    }

            protected:
                Node *current;

                Object & retrieve() cosnt
                {
                    return current->data;
                }
                const_iterator(Node *p) : current(p)
                {
                }
                friend class List<Object>;
        };
        class iterator : public const_iterator
        {
            public:
                iterator()
                {
                }
                Object & operator* ()
                {
                    return retrieve();
                }
                const Object & operator* () const
                {
                    return const_iterator::operator*();
                }
                iterator & operator++()
                {
                    iterator old = *this;
                    ++(*this);
                    return old;
                }

            protected:
                iterator(Node *p) : const_iterator(p)
                {
                }

                friend class List<object>;
        };
    public:
        List()
        {
            init();
        }
        List(const List & rhs)
        {
            init();
            *this = rhs;
        }
        ~List()
        {
            clear();
            delete head;
            delete tail;
        }
        const List & operator =(const List & rhs)
        {
            if(this == &rhs)
                return *this;
            clear();
            for(const_iterator itr = rhs.begin();itr!=rhs.end();++itr)
                push_back(*itr);
            return *this;
        }
        void init()
        {
            theSize = 0;
            head = new Node;
            tail = new Node;
            head->next = tail;
            tail->prev = head;
        }

        iterator begin()
        {
            return iterator(head->next);
        }
        const_iterator begin() const
        {
            return const_iterator(head->next);
        }
        iterator end()
        {
            return iterator(tail);
        }
        const_iterator end() const
        {
            return const_iterator(tail);
        }

        int size() const
        {
            return theSize;
        }
        bool empty() const
        {
            return size() == 0;
        }
        void clear()
        {
            while(!empty())
                pop_front();
        }
        Object & front()
        {
            return *begin();
        }
        const Object & front() const
        {
            return *begin();
        }
        Object & back()
        {
            return *--end();
        }
        const Object & back() const
        {
            return *--end();
        }
        void push_front(const Object & x)
        {
            insert(begin(),x);
        }
        void push_back(const Object & x)
        {
            insert(end(),x);
        }
        void pop_front()
        {
            erase(begin());
        }
        viod pop_back()
        {
            erase(end());
        }

        iterator insert(iterator itr,const Object & x)
        {
        }
        iteratro erase(iterator itr )
        {
        }
        iterator erase(iterator start,iterator end)
        {
        }

private:
    int theSize;
    Node *head;
    Node *tail;

    void init()
    {
    }
}