链表：用C/C++实现单链表的增删改查

#include<iostream>
using namespace std;

typedef struct LNode {  //定义链表的结构
    int data;
    struct LNode* next;
}LNode,*LinkList;

void create(LinkList& l)  
// 头插法建立带头结点的链表，输入小于0的数值视为终止
{
    l = (LinkList)malloc(sizeof(LNode));
    int x;
    l->next = NULL;
    cin >> x;
    do
    {
        LNode* s = (LNode*)malloc(sizeof(LNode));
        s->data = x;
        s->next = l->next;
        l->next = s;
        cin >> x;
    } while (x > 0);
}

void tailCreate(linkList& l)
{
l = (linkList)malloc(sizeof(LNode));
int data;
l->next = NULL;
cin >> data;
linkList ptr = l;
while (data > 0)
{
linkList p = (linkList)malloc(sizeof(LNode));
p->data = data;
ptr->next = p;
p->next = NULL;
ptr = p;
cin >> data;
}
}

void dis(LinkList l)  //输出链表
{
    cout << "当前链表为："<<endl;
    while (l->next != NULL)
    {
        cout << l->next->data << " ";
        l = l->next;
    }
    cout << endl;
}

LinkList insert(LinkList& l, int x)  //头插法插入结点在链表开头
{
    LNode* s = (LNode*)malloc(sizeof(LNode));
    s->data = x;
    s->next = l->next;
    l->next = s;
    return l;
}
int getNumber(LinkList l, int x)//按照值查找结点序号，返回序号
{
    int i = 0;
    while (l != NULL)
    {
        i++;
        if (l->data == x)
        {
            cout << "find x=" << x << " ,num=" << i - 1 << endl;
            break;
        }
        l = l->next;
    }
    return i;
}
LNode* getElement(LinkList l, int no)//按照序号查找结点并返回结点
{
    LNode* s = l->next;
    int j = 1;
    while (s->next != NULL && j < no)
    {
        s = s->next;
        j++;
    }
    cout <<"find No."<<no<<" is "<< s->data << endl;
    return s;
}

void delect(LinkList& l, int no)//删除指定序号的节点
{
    if (no == 1)  
//因为第一个元素的前驱结点是头结点，所以单独处理删除第一个元素的情况
    {
        LNode* s = l;
        LNode* p = l->next;
        l->next = p->next;
        free(p);
    }
    else
    {
        LNode* s = getElement(l, no - 1);  //先找到它的前驱结点
        LNode* p;
        p = s->next;
        s->next = p->next;
        cout << "delect " << p->data << " success" << endl;
        free(p);
    }
}
void reverseList(LinkList& l)  //将链表倒序
{
    LNode* s = (LNode*)malloc(sizeof(LNode));
    LNode* p = (LNode*)malloc(sizeof(LNode));
    s = l->next;
    l->next = NULL;
    while (s!= NULL)
    {
        p = s->next;
        s->next = l->next;
        l->next = s;
        s = p;
    }
}

int main(void)
{
    LinkList l;
    int x, no;
    cout << "输入正整数插入链表，输入负整数后结束输入：" << endl;
    create(l);//输入链表
    dis(l); //输出链表
    cout << "输入要插入在链表前端的数值：" << endl;
    cin >> x;
    insert(l,x);
    dis(l);
    cout << "输入要查找的结点数值：" << endl;
    cin >> x;
    getNumber(l,x);//根据数组查找第一个对应的结点
    cout << "输入要查找的结点序号(1~n)：" << endl;
    cin >> no;
    getElement(l,no);//根据序号查找对应的数值
    cout << "输入要删除的结点序号(1~n)：" << endl;
    cin >> no;
    delect(l,no);//删除指定序号的结点
    dis(l);
    reverseList(l);//反转链表
    dis(l);
}