C语言实现无头节点单链表

来源：互联网发布：wow3.35数据库编辑：程序博客网时间：2024/04/30 04:01

测试代码

singlelinkedlist.h头文件

#ifndef __SINGLELINKEDLIST_H__#include<stdio.h>#include<windows.h>#include<assert.h>typedef int DataType;typedef struct ListNode{    DataType data;    struct ListNode *next;}ListNode;ListNode *InitList(DataType num);//初始化并赋值void PushBack(ListNode **pplist, DataType num);//尾插void PrintList(ListNode *plist);//输出void DestoryList(ListNode** pplist);//释放链表(包括环)void PopBack(ListNode **pplist);//尾删void PushFront(ListNode **pplist, DataType num);//头插void PopFront(ListNode **pplist);//头删ListNode* Find(ListNode *plist, DataType num);//查找void Insert(ListNode** pplist, ListNode* pos, DataType x);//插入void Erase(ListNode** pplist, ListNode* pos);//删除#endif//__SINGLELINKEDLIST_H__1
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singlelinkedlist.c实现部分

#include "singlelinkedlist.h"ListNode *InitList(DataType num)//定义一个新的结点{    ListNode *node = (ListNode*)malloc(sizeof(ListNode));    node->data = num;    node->next = NULL;    return node;}void PushBack(ListNode **pplist, DataType num)//尾插{    if (*pplist == NULL)//空链表    {        *pplist = InitList(num);//定义一个结点    }    else if ((*pplist)->next == NULL)//只有一个结点    {        (*pplist)->next = InitList(num);    }    else//正常情况(多个结点)    {        ListNode *tail = *pplist;        while (tail->next)        {            tail = tail->next;//依次指向下一个结点，找到为空的尾结点        }        tail->next = InitList(num);//找到以后直接添加一个结点    }}void PrintList(ListNode *plist)//打印链表{    ListNode *tail = plist;    while (tail)    {        printf("%d->", tail->data);        tail = tail->next;    }    printf("NULL");    printf("\n");}void DestoryList(ListNode** pplist)//释放链表(包括环){    assert(pplist);    ListNode* cur = *pplist;    while (cur)    {        ListNode* next = cur->next;        free(cur);        cur = next;    }    *pplist = NULL;}void PopBack(ListNode **pplist)//尾删{    if (*pplist == NULL)//空链表    {        return;    }    else if ((*pplist)->next == NULL)//只有一个结点，直接释放    {        free(*pplist);        *pplist = NULL;    }    else    {        ListNode* tail = *pplist;        ListNode* pos = tail;        while (tail->next)//tail指向pos的后一个结点        {            pos = tail;             tail = tail->next;        }        free(tail);//释放最后一个结点就相当于删除了尾结点        tail = NULL;        pos->next = NULL;    }}void PushFront(ListNode **pplist, DataType num)//头插{    if (*pplist == NULL)//空链表    {        *pplist = InitList(num);    }    else    {        ListNode *tmp = InitList(num);//开辟一个新的结点        tmp->next = *pplist;//让它指向原先的开始结点        *pplist = tmp;//pplist依然开始结点    }}void PopFront(ListNode **pplist)//头删{    if (*pplist == NULL)//空链表    {        return;    }    else if ((*pplist)->next == NULL)//只有一个结点    {        *pplist = NULL;    }    else    {        ListNode *tmp = (*pplist)->next;//tmp指向原先头结点指向的下一个位置        free(*pplist);        *pplist = tmp;    }}ListNode* Find(ListNode *plist, DataType num)//查找{    assert(plist);//断言其是否为空链表    while (plist)    {        if (plist->data == num)        {            return plist;        }        plist = plist->next;    }    return NULL;}void Insert(ListNode** pplist, ListNode* pos, DataType num)//插入{    assert(*pplist&&pos);    if (((*pplist)->next == NULL) || (pos == *pplist))        //只有开始结点或者是要插入的正好在开始结点的前面    {        PushFront(pplist, num);    }    else    {        ListNode* tmp = NULL;        ListNode* tail = *pplist;        while (tail->next != pos)        {            tail = tail->next;        }        tmp = InitList(num);        tail->next = tmp;        tmp->next = pos;    }}void Erase(ListNode** pplist, ListNode* pos)//删除{    assert(*pplist&&pos);    if (((*pplist)->next == NULL) || (*pplist == pos))    {        PopFront(pplist);    }     else    {        ListNode* tmp = *pplist;        while (tmp->next != pos)        {            tmp = tmp->next;        }        tmp->next = pos->next;        free(pos);        pos = NULL;    }}1
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test.c测试部分

#include "singlelinkedlist.h"void test(){    ListNode *list = NULL;    PushBack(&list, 1);    PushBack(&list, 2);    PushBack(&list, 3);    PushBack(&list, 4);    PrintList(list);    PopBack(&list);    PrintList(list);    PopBack(&list);    PrintList(list);    PopBack(&list);    PrintList(list);    PopBack(&list);    PrintList(list);}void test1(){    ListNode *list = NULL;    PushFront(&list, 1);    PushFront(&list, 2);    PushFront(&list, 3);    PushFront(&list, 4);    PushFront(&list, 5);    PrintList(list);    PopFront(&list);    PrintList(list);    PopFront(&list);    PrintList(list);    PopFront(&list);    PrintList(list);    PopFront(&list);    PrintList(list);    PopFront(&list);    PrintList(list);}void test2(){    ListNode *list = NULL;    PushFront(&list, 1);    PushFront(&list, 2);    PushFront(&list, 4);    PushFront(&list, 5);    PushFront(&list, 6);    PrintList(list);    ListNode *ret = Find(list, 2);    //测试使用    /*if (ret != NULL)    {        printf("%p\n", ret);    }    else    {        printf("没有这个值!\n");    }*/    Insert(&list, ret, 3);    PrintList(list);    Erase(&list, ret);    PrintList(list);}int main(){    //test();    //test1();    test2();    system("pause");    return 0;}

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