链表C++实现

节点定义：

typedef struct node {    int data;    struct node *next;}NODE;

类定义

class LinkList{private:    NODE *head;public:    LinkList() { head = NULL; }    ~LinkList();    bool clearSqList();    bool isEmpty() { return head == NULL; }    int Length();    void GetElem(int i, int *e);    int LocateElem(int e);    bool PriorElem(int cur_e, int *pre_e);    bool NextElem(int cur_e, int *next_e);    bool Insert(int i, int e);    bool Delete(int i, int *e);    NODE * Reverse();};

各个函数的作用参见下面的实现注释

实现

析构函数

//析构函数LinkList::~LinkList()//和清空一样{    NODE *p = head;    while (head)    {        p = head;        head = head->next;        delete(p);    }}

清空函数

bool LinkList::clearSqList()//清空函数，和析构一样{    NODE *p = head;    while (head)    {        p = head;        head = head->next;        delete(p);    }}

获取链表长度

//获取链表长度int LinkList::Length(){    NODE *p = head;    int len = 0;    while (p != NULL)    {        len++;        p = p->next;    }    return len;}

获取指定位置的元素

bool LinkList::GetElem(int i, int *e)//*e是返回的元素{    NODE *p = head;    int j = 0;    while (p&&j < i)    {        p = p->next;        j++;    }    if (p == NULL) return false;    *e = p->data;    return true;}

查找元素e在链表什么位置（下标位置，从0开始）

int LinkList::LocateElem(int e){    int i = 0;    NODE *p = head;    while (p != NULL)    {        if (p->data == e)            return i;        else p = p->next;        i++;    }    std::cout << "表中不存在指定元素" << std::endl;    exit(1);}

取上一个元素

bool LinkList::PriorElem(int cur_e, int *pre_e){    NODE *p = head;    if (p->data == cur_e) return false;//是头结点，不存在上一个元素    while (p->next != NULL)    {        if (p->next->data == cur_e)        {            *pre_e = p->data;            return true;        }        else            p = p->next;    }    return false;//遍历完不存在或者只有一个头结点}

取下一个元素

bool LinkList::NextElem(int cur_e, int *next_e){    NODE *p = head;    if (head == NULL || head->next == NULL) return false;    while (p->next != NULL)    {        if (p->data == cur_e)        {            *next_e = p->next->data;            return true;        }        else            p = p->next;    }    return false;}

在指定位置插入元素e

void LinkList::Insert(int i, int e){    NODE *p = head,*s;    int j = 0;    if (i == 0)    {        s = (NODE *)new NODE[1];        s->data = e;        s->next = p;        head = s;        return true;    }    while (p&&j < i - 1)    {        p = p->next;        j++;    }    if (p == NULL)        return false;//到队尾了    s= (NODE *)new NODE[1];    s->data = e;    s->next = p->next;    p->next = s;    return true;}

//删除指定位置的元素，并把删除的元素赋给*e

bool LinkList::Delete(int i, int *e){    NODE *p = head, *s;    if (p == NULL) return false;    int j = 0;    if (i == 0)    {        head = head->next;        *e = p->data;        delete p;        p = NULL;        return true;    }    while (p&&j < i - 1)    {        j++;        p = p->next;    }    if (p == NULL)        return false;    s = p->next;    p->next = p->next->next;    *e = s->data;    delete s;    s = NULL;    return true;}

//反转一个链表

NODE* LinkList::Reverse(){    if (head == NULL || head->next == NULL) return head;    NODE *p = head,*q=head->next,*r;    head->next = NULL;    while (q)    {        r = q->next;        q->next = p;        p = q;        q = r;    }    head = p;    return head;}

验证

#include<iostream>#include"LinkList.h"using namespace std;int main(){    int a = 0;    int *p = &a;    LinkList li;    li.Insert(0, 5);    li.Insert(1, 4);    li.Insert(2, 12);    li.Insert(3, 5);    li.Insert(3, 6);    li.Insert(1, 7);    cout <<"链表长度"<< li.Length()<<endl;    cout << "各个元素的值是：";    for (int i = 0;i < li.Length();i++)//遍历该链表    {        if (li.GetElem(i, p))            cout << *p<<"   ";    }    cout << endl;    cout << "反转后各个元素的值是：";    NODE* re_li=li.Reverse();    while (re_li)    {        cout << re_li->data << "   ";        re_li = re_li->next;    }    cout << endl;}