C链表操作

#define  _CRT_SECURE_NO_WARNINGS 
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

typedef struct Node
{
    int data;
    struct Node *next;
}SLIST;

SLIST *SList_Create(); //创建链表
int SList_Print(SLIST *pHead); //遍历链表
int SList_NodeInsert(SLIST *pHead, int x, int y); //插入值  在x值之前 删除y
int SList_NodeDel(SLIST *pHead, int y);
int SList_Destory(SLIST *pHead);

//创建链表
SLIST *SList_Create()
{

    SLIST *pHead,/*头节点*/  *pM,/*新节点*/ *pCur/*尾节点*/;
    int        data;
    //创建头节点 并初始化
    pHead = (SLIST *)malloc(sizeof(SLIST));
    if (pHead == NULL)
    {
        return NULL;
    }
    pHead->data = 0;
    pHead->next = NULL;

    printf("\nplease enter you data: ");
    scanf("%d", &data);

    pCur = pHead;

    while (data != -1)
    {
        //创建业务节点 并初始化 不断接受输入 malloc新结点
        pM = (SLIST *)malloc(sizeof(SLIST));
        if (pM == NULL)
        {
            return NULL;
        }
        pM->data = data;
        pM->next = NULL;

        //2 新结点 入链表 
        pCur->next = pM;

        //3 新结点变成当前节点
        pCur = pM;  //链表结点的尾部追加 

        printf("\nplease enter you data: ");
        scanf("%d", &data);
    }

    return pHead;
}

//打印链表
int SList_Print(SLIST *pHead)
{
    SLIST *tmp = NULL;
    if (pHead == NULL)
    {
        return -1;
    }
    tmp = pHead->next;

    printf("\nBegin\t");
    while (tmp)
    {
        printf("%d ", tmp->data);
        tmp = tmp->next;
    }
    printf("\tEnd");
    return 0;
}

//插入节点
int SList_NodeInsert(SLIST *pHead, int x, int y)
{
    SLIST *pM, *pCur, *pPre;

    //创建新的业务节点pM
    pM = (SLIST *)malloc(sizeof(SLIST));
    if (pM == NULL)
    {
        return -1;
    }
    pM->next = NULL;
    pM->data = y;

    //遍历链表
    pPre = pHead;
    pCur = pHead->next;

    while (pCur)
    {
        if (pCur->data == x)
        {
            break;
        }
        pPre = pCur;
        pCur = pCur->next;
    }

    //让新结点 连接 后续链表
    pM->next = pPre->next;
    //让前驱节点 连接 新结点
    pPre->next = pM;

    return 0;
}
//删除节点
int SList_NodeDel(SLIST *pHead, int y)
{
    SLIST  *pCur, *pPre;

    //初始化状态

    pPre = pHead;
    pCur = pHead->next;

    while(pCur != NULL)
    {
        if (pCur->data == y)
        {
            break;
        }
        pPre = pCur;
        pCur = pCur->next;
    }

    //删除操作
    if (pCur == NULL)
    {
        printf("没有找到结点值为:%d 的结点\n", y);
        return -1;
    }
    pPre->next = pCur->next;
    if (pCur != NULL)
    {
        free(pCur);
    }
    return 0;
}

int SList_Destory(SLIST *pHead)
{
    SLIST *tmp = NULL;
    if (pHead == NULL)
    {
        return -1;
    }
    
    while (pHead != NULL)
    {
        tmp = pHead->next;//下一个节点缓存下来
        free(pHead);
        pHead = tmp;//tmp变成了head
    }
    return 0;
}

int SList_Reverse(SLIST *pHead)
{
    SLIST    *p = NULL; //前驱指针
    SLIST    *q = NULL; //当前指针
    SLIST    *t = NULL; //缓存的一个结点

    if (pHead==NULL || pHead->next == NULL ||pHead->next->next ==NULL )
    {
        return 0;
    }
    
    //初始化     //前驱结点
    p = pHead->next;
    q = pHead->next->next;

    //p = pHead;  //代码能兼容
    //q = pHead->next;
    
    //一个结点 一个结点的逆置
    while(q)
    {
        t = q->next; //缓冲后面的链表

        q->next = p;    //逆置

        p = q; //让p下移一个结点

        q = t;
    }

    //头节点 变成 尾部结点 后  置null
    pHead->next->next = NULL;
    pHead->next = p;  //

    return 0;
}
void main()
{
    int  ret = 0;

    SLIST *pHead = NULL;
    pHead = SList_Create();
    ret = SList_Print(pHead);

    ret = SList_NodeInsert(pHead, 20, 19);
    ret = SList_Print(pHead);

    ret = SList_NodeDel(pHead, 19);
    ret = SList_Print(pHead);

    ret =  SList_Reverse(pHead);
    ret = SList_Print(pHead);

    SList_Destory(pHead);

    printf("hello...\n");
    system("pause");
    return ;
}