C语言实现单链表——之基本操作1

一般面试题中会考虑无头节点的单链表下面是一些实现：
声明Sqlist.h文件

#pragma once#include <assert.h>#include <stdio.h>typedef int Datatype;typedef struct SList{    Datatype data;    struct SList* next;}SList, *PSlist;//无头结点// 初始化单链表(对于无头结点单链表，该函数没有意义)void InitList(PSlist* pHead);// 销毁单链表void DestroyList(PSlist* pHead);// 尾插void PushBack(PSlist* pHead, Datatype data);// 尾出void PopBack(PSlist* pHead);// 头插void PushFront(PSlist* pHead, Datatype data);// 头出void PopFront(PSlist* pHead);// 在链表中查找元素dataPSlist Find(PSlist pHead, Datatype data);// 删除pos位置的结点(注意不能用那种替换形式)void  Erase(PSlist* pHead, PSlist pos);// 在链表的pos位置插入元素datavoid  Insert(PSlist* pHead, PSlist pos, Datatype data);void PrintList(PSlist pHead);

函数实现：

#pragma once#include "Sqlist.h"void InitList(PSlist* pHead){    assert(pHead);    *pHead = NULL;    return;}void PrintList(PSlist pHead)////?????{    while (pHead)    {        printf("%d->", pHead->data);        pHead = pHead->next;    }    printf("NULL\n");}PSlist BuyNode(Datatype data){    PSlist pNew = (PSlist)malloc(sizeof(SList));    if (pNew == NULL)    {        return NULL;    }    pNew->next = NULL;    pNew->data = data;    return pNew;}void PushBack(PSlist* pHead, Datatype data){    assert(pHead);    PSlist pNewNode = BuyNode(data);    PSlist pTemp = *pHead;    if (pTemp == NULL)    {        *pHead =pNewNode;        return;    }    while (pTemp->next != NULL)    {        pTemp = pTemp->next;    }    pTemp->next = pNewNode;}void PopBack(PSlist* pHead){    assert(pHead);    PSlist pPre = *pHead;    if (pPre == NULL)    {        return;    }    if (pPre->next == NULL)    {        free(pPre);        pPre = NULL;        *pHead = NULL;    }    if (pPre != NULL)    {        PSlist pDel = pPre->next;        while (pDel->next != NULL)        {            pPre = pPre->next;            pDel = pDel->next;        }        pPre->next = NULL;        pDel->next = NULL;        free(pDel);    }    return;}void PushFront(PSlist* pHead, Datatype data){    assert(pHead);    PSlist pNew = BuyNode(data);    if (pNew == NULL)    {        return;    }    pNew->next = *pHead;    *pHead = pNew;//}void PopFront(PSlist* pHead){    assert(NULL != pHead);    PSlist pCur = *pHead;    if (pCur == NULL)    {        return;    }    else    {        *pHead = pCur->next;        free(pCur);        pCur->next = NULL;    }}PSlist Find(PSlist pHead, Datatype data){    assert(pHead);    while (pHead)    {        if(pHead->data == data)            return pHead;        pHead = pHead->next;    }    return NULL;}void Erase(PSlist* pHead, PSlist pos)//1无节点 //2有节点{    PSlist pPrepos = *pHead;    assert(NULL != pos);    assert(NULL != pHead);    if (pos == *pHead)    {        PSlist pCur = *pHead;        *pHead = pos->next;        free(pCur);        pCur->next = NULL;    }    else    {        while (pPrepos->next!= pos)        {            pPrepos = pPrepos->next;        }        pPrepos->next = pos->next;        free(pos);        pos->next = NULL;    }}void  Insert(PSlist* pHead, PSlist pos, Datatype data)//后插{    assert(NULL != pHead);    assert(NULL != pos);    PSlist pNew = BuyNode(data);    if (pNew == NULL)    {        return;    }    pNew->next = pos->next;    pos->next = pNew;}

测试函数：

#include "SList.h"//Init Print Pushbackvoid Fun1(){    PSlist slist;    InitList(&slist);    PushBack(&slist,1);    PushBack(&slist,2);    PushBack(&slist, 3);    PushBack(&slist, 4);    PopBack(&slist);    PopBack(&slist);    PopBack(&slist);    PopBack(&slist);    PopBack(&slist);    PrintList(slist);}//PushFront PopFrontvoid Fun2(){    PSlist slist;    InitList(&slist);    PushFront(&slist, 1);    PushFront(&slist, 2);    PushFront(&slist, 3);    PushFront(&slist, 4);    PopFront(&slist);    PopFront(&slist);    PopFront(&slist);    PopFront(&slist);    PrintList(slist);}//Erase Findvoid Fun3(){    PSlist slist;    InitList(&slist);    PushFront(&slist, 1);    PushFront(&slist, 2);    PushFront(&slist, 3);    PushFront(&slist, 4);    //Erase(&slist, Find(slist, 4));    Insert(&slist, Find(slist, 4), 8);//找不到该位置就是NULL，assert(pos)会报错    PrintList(slist);}