链表相关操作

#include <iostream>
using namespace std;
typedef struct list
{
    int data;
    struct list* next;
    list():data(0),next(NULL){}
}List;

//1. 后插法插入数据
void insertData(List *p, int data)
{
    if (p == NULL)
        return;

    //申请空间
    List *tmp = (List *)malloc(sizeof(List));
    tmp->data = data;
    tmp->next = NULL;

    //插入链表
    while (p->next != NULL)
        p = p->next;
    p->next = tmp;
}
//2. 打印数据
void printData(List *p)
{
    while (p != NULL)
    {
        cout << p->data << endl;
        p = p->next;
    }
}

//3.链表逆序1
/*******************************************
三个指针，pre,cur,next
先保存cur的next到next中；
然后cur->next指向前面的；
pre和cur向前推进，next只是临时存储cur->next
*******************************************/
List* revertList(List *p)
{
    List *pre  = nullptr;
    List *next = nullptr;
    while (p != nullptr)
    {
        next = p->next;
        p->next = pre;
        pre = p;
        p = next;
    }
    return pre;
}
//4.链表逆序2
/***********************************
将链表看成两个结点，头结点和后面整体
***********************************/
List* revertList2(List *p)
{
    List *newphead;
    if ((p == NULL) || (p->next == NULL))
        return p;
    newphead = revertList2(p->next);
    p->next->next = p;
    p->next = NULL;
    return newphead;
}


int main()
{
    List *phead = new List;
    for (int i = 0; i < 20; i++)
    {
        insertData(phead, i);
    }

    printData(phead);

    phead=revertList(phead);

    printData(phead);
    cout << "AAAAAAAAAAAAA" << endl;
    phead = revertList2(phead);

    printData(phead);


    return system("pause");
}