双链表的实现C++封装

双链表的C++实现，先给出主要算法，最后而给出完整的实现。

定义节点

//定义节点typedef class Node{public://数据int data;//前指针class Node *prior;//后指针class Node *next;}ListNode;

头插法插入元素节点

//创建并初始化（头插法）List(int a[], int n){int i;ListNode *p;L = (ListNode *)malloc(sizeof(ListNode));L->next = L->prior = NULL;for (i = 0; i < n; i++){p = (ListNode *)malloc(sizeof(ListNode));p->data = a[i];p->next = L->next;//将p后一个节点地址赋给l->nextif (L->next != NULL){L->next->prior = p;//将L后一节点的前指针赋值为带插入指针地址}p->prior = L;//带插入前指针赋值为LL->next = p;//L后指针赋值为p}}

尾插法插入节点

//尾插法List(int a[], int n){int i;ListNode *p, *s;//初始化表头L = (ListNode *)malloc(sizeof(ListNode));L->prior = NULL;//使p指向尾节点，初始时头结点即为尾节点p = L;//生成新节点，插入元素，链上节点for (i = 0; i < n; i++){s = (ListNode *)malloc(sizeof(ListNode));s->data = a[i];//前指针指向尾结点s->prior = p;//尾指针指向新节点p->next = s;//将新节点变成为节点p = s;}p->next = NULL;}

释放双链表

//析构并释放空间~List(){ListNode *pre = L, *p = L->next;while (p != NULL){free(pre);pre = p;p = pre->next;//p指向下下个节点}free(pre);//下个节点}

判断是否为空

//判断是否为空bool isEmpty(){return (L->next == NULL);}

返回链表长度

//返回长度int GetLength(){int i = 0;ListNode *p = L;while (p->next != NULL){//p->next为当前节点的指针域i++;p = p->next;}return i;}

输出链表元素

//输出链表void DispleyList(){ListNode *p = L->next;while (p != NULL){cout << p->data << ends;p = p->next;}cout << endl;}

按元素位置查找并返回值

//按序号查找并返回值bool getElem(int i, int &res){ListNode *p = L;int j = 0;while (j != i&&p->next != NULL){j++;p = p->next;}//讨论退出的情况if (j != i&&p->next == NULL){return false;}else{res = p->data;return true;}}

按值查找并返回位置

//按值查找并返回序号int LocateElem(int elem){ListNode *p = L;int i = 0;while (p->next != NULL&&p->data!=elem){i++;p = p->next;}//讨论退出的情况if (p->next == NULL&&p->data != elem){return 0;}else{return i;}}

插入新节点

//插入元素void InsertElem(int i, int &res){i--;//找到插入位置的前一个节点int j = 0;ListNode *p = L, *s;while (j != i&&p->next != NULL){j++;p = p->next;}//讨论退出情况if (j != i&&p->next == NULL){cout << "error No." << endl;}else{s = (ListNode *)malloc(sizeof(ListNode));s->data = res;//链上后继节点，当前节点的指针域赋值为p的后继节点s->next = p->next;//插入当前节点，下一节点的前指针指向当前节点p->next->prior = s;//p的后指针域赋值为当前节点p->next = s;//当前节点的前指针赋值为ps->prior = p;}}

删除某一节点

//删除元素并返回值bool DeleteElem(int i,int &res){i--;ListNode *p = L, *s;int j = 0;while (j != i&&p->next != NULL){j++;p = p->next;}if (j != i&&p->next == NULL){return false;}else{//记录p的下一个节点的地址s = p->next;//得到数据res = s->data;//p的后指针域存储p的下一个的下一个节点p->next = p->next->next;//p的下一个的下一个节点的前指针域赋值为p的地址p->next->next->prior = p;//释放free(s);return true;}}

以上便是完整的双链表算法C++实现，下面附上完整代码

#include<iostream>using namespace std;const int MAX_N = 100;//定义节点typedef class Node{public://数据int data;//前指针class Node *prior;//后指针class Node *next;}ListNode;class List{public://创建并初始化（头插法）//List(int a[], int n){//int i;//ListNode *p;//L = (ListNode *)malloc(sizeof(ListNode));//L->next = L->prior = NULL;//for (i = 0; i < n; i++){//p = (ListNode *)malloc(sizeof(ListNode));//p->data = a[i];//p->next = L->next;//将p后一个节点地址赋给l->next//if (L->next != NULL){//L->next->prior = p;//将L后一节点的前指针赋值为带插入指针地址//}//p->prior = L;//带插入前指针赋值为L//L->next = p;//L后指针赋值为p//}//}//尾插法List(int a[], int n){int i;ListNode *p, *s;//初始化表头L = (ListNode *)malloc(sizeof(ListNode));L->prior = NULL;//使p指向尾节点，初始时头结点即为尾节点p = L;//生成新节点，插入元素，链上节点for (i = 0; i < n; i++){s = (ListNode *)malloc(sizeof(ListNode));s->data = a[i];//前指针指向尾结点s->prior = p;//尾指针指向新节点p->next = s;//将新节点变成为节点p = s;}p->next = NULL;}//析构并释放空间~List(){ListNode *pre = L, *p = L->next;while (p != NULL){free(pre);pre = p;p = pre->next;//p指向下下个节点}free(pre);//下个节点}//判断是否为空bool isEmpty(){return (L->next == NULL);}//返回长度int GetLength(){int i = 0;ListNode *p = L;while (p->next != NULL){//p->next为当前节点的指针域i++;p = p->next;}return i;}//输出链表void DispleyList(){ListNode *p = L->next;while (p != NULL){cout << p->data << ends;p = p->next;}cout << endl;}//按序号查找并返回值bool getElem(int i, int &res){ListNode *p = L;int j = 0;while (j != i&&p->next != NULL){j++;p = p->next;}//讨论退出的情况if (j != i&&p->next == NULL){return false;}else{res = p->data;return true;}}//按值查找并返回序号int LocateElem(int elem){ListNode *p = L;int i = 0;while (p->next != NULL&&p->data!=elem){i++;p = p->next;}//讨论退出的情况if (p->next == NULL&&p->data != elem){return 0;}else{return i;}}//插入元素void InsertElem(int i, int &res){i--;//找到插入位置的前一个节点int j = 0;ListNode *p = L, *s;while (j != i&&p->next != NULL){j++;p = p->next;}//讨论退出情况if (j != i&&p->next == NULL){cout << "error No." << endl;}else{s = (ListNode *)malloc(sizeof(ListNode));s->data = res;//链上后继节点，当前节点的指针域赋值为p的后继节点s->next = p->next;//插入当前节点，下一节点的前指针指向当前节点p->next->prior = s;//p的后指针域赋值为当前节点p->next = s;//当前节点的前指针赋值为ps->prior = p;}}//删除元素并返回值bool DeleteElem(int i,int &res){i--;ListNode *p = L, *s;int j = 0;while (j != i&&p->next != NULL){j++;p = p->next;}if (j != i&&p->next == NULL){return false;}else{//记录p的下一个节点的地址s = p->next;//得到数据res = s->data;//p的后指针域存储p的下一个的下一个节点p->next = p->next->next;//p的下一个的下一个节点的前指针域赋值为p的地址p->next->next->prior = p;//释放free(s);return true;}}private:ListNode *L;};int main(){int i, n, a[MAX_N], res = 0;cout << "Input length:";cin >> n;for (i = 0; i < n; i++){cin >> a[i];}//构建单链表List m_list(a, n);//输出m_list.DispleyList();//判断是否为空，非空输出长度if (!m_list.isEmpty()){cout << "It is not empty." << endl;cout << "It contained " << m_list.GetLength() << " elements." << endl;}else{cout << "It is empty." << endl;}//按序号查找并返回值cout << "Input a number for querry:";cin >> i;if (m_list.getElem(i, res)){cout << "Location: " << i << " ,element: " << res << endl;}else{cout << "Loaction " << i << " is invalid." << endl;}//按值查找并返回序号cout << "Input a element for querry:";cin >> res;if (m_list.LocateElem(res) == 0){cout << "Not contain this element." << endl;}else{cout << "Element: " << res << " ,No. is :" << m_list.LocateElem(res) << endl;}//插入cout << "Input NO. and element for insert:";cin >> i >> res;m_list.InsertElem(i, res);m_list.DispleyList();//删除cout << "Input NO. for delete:";cin >> i;if (!m_list.DeleteElem(i, res)){cout << "Invalid NO." << endl;}else{cout << "NO. :" << i << " ,Element: " << res << " is deleted." << endl;}m_list.DispleyList();return 0;}

测试运行结果