链表2

一. 单链链表

　　1.1. 单链链表的主体

　　　　a. 此处链表的主体包含数据和节点，与linux内核中链表的用法很不一样，详细可以查看内核中链表的使用

　　　　b. 链表节点中由真实数据和下个节点指针构成。

struct node
{
    int data;
    struct node *pNext;
};

 　　1.2. 链接的创建

struct node *creat_node(int data)
{
    struct node *p = (struct node *)malloc(sizeof(struct node));
    if(NULL == p)
    {
        printf("malloc fail\n");
        return NULL;
    }
    p->data = data;
    p->pNext = NULL;
    return p;
}

　　1.3. 从头插入新节点

int insert_head(struct node *pHeader,struct node *newNode)
{
    if(NULL == newNode || NULL==pHeader)
    {
         printf("point is empty\n");
         return -1;
    }
    newNode->pNext = pHeader->pNext;
    pHeader->pNext = newNode;
    pHeader->data++;
    return 0;
}

　　1.4. 遍历链表

int loop_node(struct node *pHeader)
{
    struct node *p = pHeader;
    if(NULL==pHeader)
    {
         printf("point is empty\n");
         return -1;
    }
    while(NULL != p->pNext)
    {
        p = p->pNext;
        printf("node = %d\n",p->data);        
    }
    return 0;
}

　　1.5. 链表反转

void reverse_node(struct node *pHeader)
{
    struct node *p = pHeader->pNext;
    struct node *pbackup = NULL;
    if(NULL == pHeader || NULL == p)
    {
        printf("node should more one\n");
        return;
    }
    while(NULL != p)
    {
        pbackup = p->pNext;
        if(pHeader->pNext == p)
        {
            p->pNext = NULL;
        }
        else
        {
            p->pNext = pHeader->pNext;
            pHeader->pNext = p;
        }
        p = pbackup;
    }
}

二. 实例

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

//#define DEBUG_VERSION

#ifdef DEBUG_VERSION
    #define DEBUG_Printf(format) printf(format)
#else 
    #define DEBUG_Printf(format)
#endif

#define STR1(R)  #R
#define STR2(R)  STR1(R)
struct node
{
    int data;
    struct node *pNext;
};

struct node *creat_node(int data)
{
    struct node *p = (struct node *)malloc(sizeof(struct node));
    if(NULL == p)
    {
        printf("malloc fail\n");
        return NULL;
    }
    p->data = data;
    p->pNext = NULL;
    return p;
}

int insert_head(struct node *pHeader,struct node *newNode)
{
    if(NULL == newNode || NULL==pHeader)
    {
         printf("point is empty\n");
         return -1;
    }
    newNode->pNext = pHeader->pNext;
    pHeader->pNext = newNode;
    pHeader->data++;
    return 0;
}

int loop_node(struct node *pHeader)
{
    struct node *p = pHeader;
    if(NULL==pHeader)
    {
         printf("point is empty\n");
         return -1;
    }
    while(NULL != p->pNext)
    {
        p = p->pNext;
        printf("node = %d\n",p->data);        
    }
    return 0;
}

void reverse_node(struct node *pHeader)
{
    struct node *p = pHeader->pNext;
    struct node *pbackup = NULL;
    if(NULL == pHeader || NULL == p)
    {
        printf("node should more one\n");
        return;
    }
    while(NULL != p)
    {
        pbackup = p->pNext;
        if(pHeader->pNext == p)
        {
            p->pNext = NULL;
        }
        else
        {
            p->pNext = pHeader->pNext;
            pHeader->pNext = p;
        }
        p = pbackup;
    }
}
int main(void)
{
    
    struct node *pHeader = creat_node(0);
    insert_head(pHeader,creat_node(123));
    insert_head(pHeader,creat_node(5));
    insert_head(pHeader,creat_node(3));
#ifdef DEBUG_VERSION
    printf("len =%d\n",strlen(STR2(DEBUG_Printf())));   
#endif 
    loop_node(pHeader);
    reverse_node(pHeader);
    printf("reverse_node:\n");
    loop_node(pHeader);
    return 0;
}