双链表基本操作C++实现

主要实现双链表如下功能:

void AddBack(T val); //链表尾部添加元素

void AddFront(T val); //链表头部添加元素

bool InsertAt(int pos, T val); //在指定的索引处插入元素

bool RemoveBack(); //尾部删除元素

bool RemoveFront(); //头部删除元素

bool RemoveAt(int pos); //删除指定索引处元素

bool Find(T val); //找到元素返回索引,没找到返回-1

void Clear(); //清空链表

bool IsEmpty();//判断链表是否为空

int Size(); //返回链表元素个数

1.定义链表节点类

template<class T>

class DNode

{

public:

~DNode(void){ }

T val; //节点值

DNode<T>* next; //指向后面节点指针

DNode<T>* prior; //指向前面节点指针

DNode(T nVal)

{

val = nVal;

next = prior = NULL;

}

DNode(void){}

};

2.双链表类定义

#include "DNode.h"

#include <iostream>

using namespace std;

template<class T>

class DLinkList

{

int size;

public:

DNode<T>* head; //指向头部的指针

DNode<T>* tail; //指向尾部指针

DLinkList(void)

{

head = tail = NULL;

size = 0;

}

~DLinkList(void){ Clear(); }

void AddBack(T val) //尾部添加元素

{

DNode<T>* pNode = new DNode<T>(val);

if(head == NULL) //链表为空时

{

head = tail = pNode;

}

else{

tail->next = pNode;

pNode->prior = tail;

tail = pNode; //新节点是尾部节点

}

size ++;

}

void AddFront(T val) //头部添加元素

{

DNode<T>* pNode = new DNode<T>(val);

if(head == NULL) //链表为空时

{

head = tail = pNode;

}

else{

head->prior = pNode;

pNode->next = head;

head = pNode;

}

size ++;

}

bool InsertAt(int
pos, T val) //任意位置插入元素

{

DNode<T>* pNode = NULL;

if(pos < 0 || pos > size){

cout<<"out of range"<<endl;

returnfalse;

}

pNode = new DNode<T>(val);

if(pos == 0) // 头部位置

AddFront(val);

elseif(pos
== size - 1)

AddBack(val);

else{

DNode<T>* priorNode = GetPointerAt(pos - 1);

pNode->next = priorNode->next;

pNode->prior = priorNode;

priorNode->next->prior = pNode;

priorNode->next = pNode;

}

size++;

return true;

}

bool RemoveAt(int
pos) //删除指定索引处元素

{

DNode<T>* pNode =NULL;

if(size == 0){

cout<<"list is empty"<<endl;

returnfalse;

}

if(pos < 0 || pos > size - 1){

cout<<"out of range"<<endl;

returnfalse;

}

if(size == 1)

Clear();

else{

if(pos == 0) //头部位置

{

pNode = head;

head = head->next;

head->prior = NULL;

delete pNode;

}

else{

DNode<T>* priorNode = GetPointerAt(pos - 1);

pNode = priorNode->next;

priorNode->next = pNode->next;

pNode->next->prior = priorNode;

delete pNode;

if(pos == size - 1) //如果是尾部元素

tail = priorNode;

}

}

}

bool RemoveBack(){return
RemoveAt(size - 1);}

bool RemoveFront(){return
RemoveAt(0);}

int Find(T val)

{

int index = 0;

DNode<T>* ip = head;

while(ip != NULL){

if(ip->val == val)

return index;

ip = ip->next;

index++;

}

return -1;

}

bool IsEmpty(){return
size == 0 ?true:false;}

int Size(){return
size;}

void Clear(){

while(head != NULL){

DNode<T>* tmp = head->next;

delete head;

head = tmp;

}

tail = NULL;

size = 0;

}

private:

DNode<T>* GetPointerAt(int pos)

{

DNode<T>* pNode = NULL;

if(pos < 0 || pos>size - 1)

cout<<"out of range"<<endl;

else{

pNode = head;

for(int
i = 1; i<= pos; i++)

pNode = pNode->next;

}

return pNode;

}

};