单链表的基本操作（不带头结点）

1. Node.h

#ifndef NODE_H
#define  NODE_H
//不带头结点的单链表
typedef struct NODE
{
    int value;
    struct NODE* next;

}Node,*pNode;

#endif // NODE_H

1. List.h

#ifndef LIST_H
#define LIST_H
#include "Node.h"

//头插
void InsertByHead(pNode *pHead, int value);
//尾插
void InsertByTail(pNode *pHead, int value);
//头删
void DeleteByHead(pNode *pHead);
//尾删
void DeleteByTail(pNode *pHead);
//按值查找
pNode FindByValue(pNode pHead, int value);
//按索引查找
pNode FindByIndex(pNode pHead, int index);
//按值修改
void UpdateByValue(pNode pHead, int oldval, int newval);
//获取链表长度
int GetLength(pNode pHead);
//按索引修改
void UpdateByIndex(pNode pHead, int index, int value);
//按索引插入
void InsertByIndex(pNode *pHead, int index, int value);
//按值删除
void DeleteByValue(pNode *pHead, int value);
//按索引删除
void DeleteByIndex(pNode *pHead, int index);
//链表反序（迭代）
void Reverse(pNode *pHead);
//链表反序（递归）
void ReverseLink(pNode *pHead);
//清空链表
void Clear(pNode *pHead);
//显示链表
void ShowList(pNode pHead);

#endif // !LIST_H

1. List.c

#include "Node.h"
#include <stdio.h>
#include <malloc.h>

void InsertByHead(pNode *pHead, int value)
{
    pNode pNew = (pNode)malloc(sizeof(Node));
    if (NULL == pNew)
    {
        printf("malloc free failed!\n ");
        return;
    }
    pNew->value = value;
    pNew->next = *pHead;
    *pHead = pNew;
}

void InsertByTail(pNode *pHead, int value)
{
    if (NULL ==*pHead)
    {
        InsertByHead(pHead, value);

    }
    else
    {
        pNode pNew = (pNode)malloc(sizeof(Node));
        if (NULL == pNew)
        {
            printf("malloc free failed!\n ");
            return;
        }
        pNew->value = value;
        pNew->next = NULL;
        pNode pos = *pHead;
        while (pos->next != NULL)
        {
            pos = pos->next;
        }
        pos->next = pNew;


    }
}

void DeleteByHead(pNode *pHead)
{
    if (*pHead != NULL)
    {
        pNode pos = *pHead;
        *pHead = pos->next;
        free(pos);
        pos = NULL;
    }
}

void DeleteByTail(pNode *pHead)
{
    if (NULL ==(*pHead)->next  || NULL == *pHead)
    {
        DeleteByHead(pHead);

    }
    else
    {
        pNode pos = *pHead;
        while (pos->next->next != NULL)
        {
            pos = pos->next;
        }
        free(pos->next);
        pos->next = NULL;
    }
}

pNode FindByValue(pNode pHead, int value)
{
    pNode pos = pHead;
    while (pos != NULL)
    {
        if (pos->value != value)
        {
            pos = pos->next;

        }
        else
            break;
    }
    return pos;
}

void UpdateByValue(pNode pHead, int oldval, int newval)
{
    pNode pos = FindByValue(pHead, oldval);
    while (pos != NULL&&pos->value == oldval)
    {
        pos->value = newval;
        pos = FindByValue(pHead, oldval);
    }

}

int GetLength(pNode pHead)
{
    pNode pos = pHead;
    int count = 0;
    while (pos != NULL)
    {
        pos = pos->next;
        count++;
    }
    return count;
}

pNode FindByIndex(pNode pHead, int index)
{
    pNode pos = pHead;
    if (index > 0 && index < GetLength(pHead) - 1)
    {

        for (int i = 0; i < index&&pos != NULL; i++)
        {
            pos = pos->next;

        }

    }
    return pos;
}

void UpdateByIndex(pNode pHead, int index, int value)
{
    pNode pos = FindByIndex(pHead, index);
    if (pos != NULL)
    {
        pos->value = value;

    }

}

void InsertByIndex(pNode *pHead, int index, int value)
{
    pNode pos = *pHead;
    if (0 == index )
    {
        InsertByHead(pHead, value);
    }
    else if (index > 0 && index <= GetLength(*pHead))
    {
        for (int i = 1; i < index && pos->next != NULL; i++)
        {
            pos = pos->next;
        }
        pNode pNew = (pNode)malloc(sizeof(Node));
        if (NULL == pNew)
        {
            printf("malloc free failed!\n ");
            return;
        }
        pNew->value = value;
        pNew->next = pos->next;
        pos->next = pNew;

    }


}

void Reverse(pNode *pHead)//非递归(迭代)
{
    if (NULL == *pHead)
    {
        return;
    }
    else
    {
        pNode p1 = *pHead;
        pNode p2 = (*pHead)->next;
        pNode p3 = NULL;
        while (p2!=NULL)
        {
            p3 = p2->next;
            p2->next = p1;
            p1 = p2;//p1指向p2结点
            p2 = p3;//p2指向p3结点
        }



        (*pHead)->next = NULL;
        *pHead = p1;

    }
}

void ReverseLink(pNode *pHead)//递归
{

    if (NULL == *pHead)
    {
        return ;

    }
    else
    {
        ReverseLink(&(*pHead)->next);//回溯部分
        printf("%d\t", (*pHead)->value);

        //(*pHead)->next = NULL;

       }

}



void DeleteByValue(pNode *pHead, int value)
{
    pNode pos = *pHead;
    while (pos->next != NULL)
    {
        if (pos->next->value != value)
        {
            pos = pos->next;
        }
        else
        {
            pNode temp = pos->next;
            pos->next = temp->next;
            free(temp);
            temp = NULL;

        }

    }
    if ((*pHead)->value == value)
    {
        DeleteByHead(pHead);
    }


}
void DeleteByIndex(pNode *pHead, int index)
{

    if (0 == index)
    {
        DeleteByHead(pHead);
    }

    else if (index > 0 && index<GetLength(*pHead))
    {
        pNode pos = *pHead;

        for (int i = 0; i < index - 1 && pos->next != NULL; i++)
        {
            pos = pos->next;
        }
        pNode temp = pos->next;
        pos->next = temp->next;
        free(temp);
        temp = NULL;
    }

}

void Clear(pNode *pHead)
{
    while ((*pHead) != NULL)
    {
        DeleteByHead(pHead);
    }

}

void ShowList(pNode pHead)
{
    pNode pos = pHead;
    while (pos != NULL)
    {
        printf("%d\t", pos->value);
        pos = pos->next;
    }
    printf("\n");
}

1. main.c

int main(void)
{
    pNode pHead = NULL;
    InsertByTail(&pHead, 1);
    InsertByTail(&pHead, 4);
    InsertByTail(&pHead, 2);
    InsertByTail(&pHead, 8);
    //ShowList(pHead);
    //InsertByTail(&pHead, 1);
    //DeleteByHead(&pHead);
    //UpdateByValue(pHead, 1, 23);
    //UpdateByIndex(pHead, 2, 55);
    //InsertByIndex(&pHead, -1, 33);
    //DeleteByIndex(&pHead,0);
    //Clear(&pHead);
    //Reverse(&pHead);
    ReverseLink(&pHead);

    //ShowList(pHead);
    return 0;
}