数据结构-List

Lis的实现:

///////////////////////////////////////////////////////////////////////////////
//
//  FileName    :   c2_list.h
//  Author      :   Jimmy Han
//  Date        :   N.A                 v1    
//              :   2014/07/13 12:30    v2    
//
///////////////////////////////////////////////////////////////////////////////
#ifndef C2_LIST_H
#define C2_LIST_H
#include <iostream>

template <class object>
class List {
private:
    struct Node{
        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++()
            {
                current = current->next;
                return *this;
            }

            const_iterator operator++(int)
            {
                const_iterator old = *this;
                ++(*this);
                return old;
            }

            const_iterator& operator--()
            {
                current = current->prev;
                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() const
                {return current->data;}
            
            //not used by List, but used by iterator, so protected
            const_iterator( Node *p) : current(p) {}
                
            friend class List<object>;
    };
    class iterator : public const_iterator {
        public:
            iterator()
                 {}
                 
            object& operator*()
            {return this->retrieve();}

            object& operator*() const
            {return const_iterator::operator*()    ;}

            //return type changed, so redefine ++
            iterator& operator++()
            {
                this->current = this->current->next;
                return *this;
            }

            const iterator operator++(int)
            {
                iterator old = *this;
                ++(*this);
                return old;
            }

            iterator& operator--()
            {
                this->current = this->current->prev;
                return *this;
            }

            const iterator operator--(int)
            {
                iterator old = *this;
                --(*this);
                return old;
            }

        protected:
            iterator(Node* p) : const_iterator(p) {}
        friend class List<object>;
    };
    
    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 iter=rhs.begin(); iter!=rhs.end(); ++iter)
            push_back(*iter);
        return *this;
    }
    
    iterator begin()
    {return iterator(head->next); }

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

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

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

    int size() const
    {return _size;}

    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());}

    void pop_back()
    {erase(--end());}

    //insert object value as x before iter
    //return the position of the new inserted object
    iterator insert(iterator iter, const object &x)
    { 
        //current is private, could be access cus of friend classs
        Node* p = iter.current;
        _size++;
        return iterator(p->prev = p->prev->next = new Node(x, p->prev, p)); 
    }

    //erase the object iter point to
    //return the next object of iter
    iterator erase(iterator iter)
    {
        if (!empty())
        {
            /* code */
            Node* p = iter.current;
            iterator retVal(p->next);
            p->prev->next = p->next;
            p->next->prev = p->prev;
            delete p;
            --_size;
            return retVal;
        }
        else
        {
            cout << "Empty List!!" << endl;
            return iter;
        }
    }

    iterator erase(iterator start, iterator end)
    {
        for(iterator iter = start; iter != end; )
            iter = erase(iter);
        return end;
    }

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

    void init()
    {
        //loop list?
        _size = 0;
        head    = new Node;
        tail         = new Node;
        head->next     = tail;
        tail->prev        = head;
    }

};

#endif

List的测试程序：

///////////////////////////////////////////////////////////////////////////////
//
//  FileName    :   c2_list.cpp
//  Author      :   Jimmy Han
//  Date        :   N.A 			    v1    
//              :   2014/07/13 12:30    v2    
//
///////////////////////////////////////////////////////////////////////////////
#include "printCollection.h"
#include "c2_list.h"
using namespace std;

int main()
{
	//List();
	List<string> slist;
	//List<string>::iterator giter;
	slist.erase(slist.begin());
	//void push_back(const object &x)
	slist.push_back("a1");
	slist.push_back("a2");
	slist.push_front("b1");
	slist.push_front("b2");
	cout << "After initilization: " << endl;
	printCollection(slist);
	cout << "Front is: " << slist.front() << endl;

	//List(const List& rhs);
	List<string> slist2 = slist;
	
	//push_front(const object &x)
	slist2.push_front("c1");
	slist2.push_front("c2");
	
	
	//pop_back()
	slist2.pop_back();
	
	//pop_front()
	slist2.pop_front();
	
	//object & front()
	cout << slist2.front() << endl;
	
	//object & back()
	cout << slist2.back() << endl;
	
	//iterator insert(const iterator &iter, object &x)
	slist2.insert(++(slist2.begin()), "d1");
	
	//erase(const_iterator iter)
	slist2.erase((slist2.begin())++);
	
	//erase(const_iterator start, const_iterator end)
		
	//begin(), end()
	for(List<string>::const_iterator iter = slist2.begin(); iter != slist2.end(); ++iter)
		cout << *iter << " ";
	cout << endl;
		
	printCollection(slist);
	
	return 0;
}