双向链表（C++）

下面是继续写的数据结构中双向链表的类（还有部分有些问题，待将所有的数据结构实现之后统一测试和修改）（记得未测试哦。）

//公元2013年3月17日
//Single List--By Paul

#ifndef _DoubleList_
#define _DoubleList_

#include<iostream>
using namespace std;

template<typename Type> class DoubleList;
//结点类

template<typename Type> class ListNode
{
private:
	 Type data;
	 ListNode *Previous;
	 ListNode *Next;
private:
	friend class DoubleList<Type>;
	ListNode():Previous(NULL),Next(NULL){}
	ListNode(const Type item,ListNode<Type> *Pprevious=NULL,ListNode<Type> *Nnext=NULL):data(item),Prevoius(Pprevious),Next(Nnext){}
	~ListNode()
	{
		Previous=NULL;
		Next=NULL;
	}
public:
	Type GetData();
};
	template<typename Type> Type ListNode<Type>:: GetData()
	{
		return this.data;
	}

	//双链表类
	template<typename Type> class DoubleList
	{
	private:
		ListNode<Type> *head;
	public:
		DoubleList():head(new ListNode<Type>())
		{
			head->Previous=head;
			head->Neat=head;
		}
		~DoubleList()
		{
			MakeEmaty();
			delete head;
		}
	public:
		void MakeEmpty();  // make the List Empty
		int Length();
		ListNode<Type> *Find(int n=0);   //查找第n个数的值
		ListNode<Type> *FindData(Type item);
		bool Insert(Type item,int n=0); //插入
		Type Remove(int n=0);
		Type Get(int n=0);
		void Print();
	};
	//函数的实现
	template<typename Type> void DoubleList<Type>::MakeEmpty()
	{
		ListNode<Type> *pmove=head->Next;
		ListNode<Type> *pdel;
		while(pmove!=head)
		{
			pdel=pmove;
			pmove=pdel->Next;
			delete pdel;
		}
		head->Next=head;
		head->Previous=head;
	}

	template<typename Type> int DoubleList<Type>::Length()
	{
		ListNode<Type> *Pprevious=head->Previous,*Nnext=head->Next;
		int count=0;
		while(1)
		{
			if(Pprevious->Next==Nnext)
			{
				break;
			}
			if(Pprevious==Nnext&&Pprevious!=head)
			{
				count++;
				break;
			}
			count+=2;
			Pprevious=Pprevious->Previous;
			Nnext=Nnext->Next;
		}
		return count;
	}

	template<typename Type> ListNode<Type>* DoubleList<Type>::Find(int n=0)
	{
		if(n<0)
		{
			cout<<"需要查找的数值不存在"<<endl;
			return NULL;
		}
		ListNode<Type> *pmove=head->Next;
		for(int i=0;i<n;i++)
		{
			pmove=pmove->Next;
			if(pmove==head)
			{
				cout<<"需要查找的数值不存在"<<endl;
				return NULL;
			}
		}
		return pmove;
	}

	template<typename Type> bool DoubleList<Type>::Insert(Type item,int n)
	{
		if(n<0)
		{
			cout<<"你的实如不合法"<<endl;
			return 0;
		}
		ListNode<Type> *newnode=new ListNode<Type>(item),*pmove=head;
		if(newnode==NULL)
		{
			cout<<"Application Error"<<endl;
			exit(1);
		}
		for(int i=0;i<n;i++)
		{
			pmove=pmove->Next;
			if(pmove==head)
			{
				cout<<"this is out of boundry"<<endl;
				return 0;
			}
		}
		//插入数据
		newnode->Next=pmove->Next;
		newnode->Previous=pmove;
		pmove->Next=newnode;
		newnode->Next->Previous=newnode;
		return 1;
	}

	template<typename Type> Type DoubleList<Type>::Remove(int n=0)
	{
		if(n<0)
		{
			cout<<"This n is out of boundry"<<endl;
			exit(1);
		}
		ListNode<Type> *pmove=head,*pdel;
		for(int i=0;i<n;i++)
		{
			pmove=pmove->Next;
			if(pmove==head)
			{
				cout<<"the n is out of boundry"<<endl;
				exit(1);
			}
		}
		//删除数据
		pdel=pmove;
		pmove->Previous->Next=pdel->Next;
		pmove->Next->Previous=pdel->Previous;
		Type temp=pdel->data;
		delete pdel;
		return temp;
	}

	template<typename Type> Type DoubleList<Type>::Get(int n=0)
	{
		if(n<0)
		{
			cout<<"this n is out of boundry"<<endl;
			exit(1);
		}
		ListNode<Type> *pmove=head;
		for(int i=0;i<n;i++)
		{
			pmove=pmove->Next;
			if(pmove==head)
			{
				cout<<"the n is out of boundry"<<endl;
				exit(1);
			}
		}
		return pmove->data;
	}

	template<typename Type> void DoubleList<Type>::Print()
	{
		ListNode<Type> *pmove=head->Next;
		cout<<"head";
		while(pmove!=head)
		{
			cout<<"----->"<<pmove->data;
			pmove=pmove->Next;
		}
		cout<<"----->over"<<endl<<endl;
	}

	template<typename Type> ListNode<Type>* DoubleList<Type>::FindData(Type item)
	{
		ListNode<Type> *Pprevious=head->Previous,*Nnext=head->Next;
		while(Pprevious->Next!=Nnext&&Pprevious!=Nnext)
		{
			if(Pprevious->data==item)
			{
				return Pprevious;
			}
			if(Nnext->data==item)
			{
				return Nnext;
			}
			Pprevious=Pprevious->Previous;
			Nnext=Nnext->Next;
		}
		cout<<"Can't find the elelment"<<endl;
		return NULL;
	}

#endif