C语言实现链表的基本操作(增，删，查，改等等)

链表是一种物理存储单元上非连续、非顺序的存储结构，数据元素的逻辑顺序是通过链表中的指针链接次序实现的。

链表由一系列结点（链表中每一个元素称为结点）组成，结点可以在运行时动态生成。

每个结点包括两个部分：一个是存储数据元素的数据域，另一个是存储下一个结点地址的指针域。

LinkList.h

#ifndef __LINKLIST_H__ 
#define __LINKLIST_H__ 

#include <stdio.h>
#include <assert.h>
#include <malloc.h>
#include <stdlib.h>

typedef int DataType;
typedef struct Node
{
	DataType data;
	struct Node* next;
}Node, *pNode, List, *pList;


//初始化链表
void InitLinkList(pList* pplist);
//创建节点
pNode BuyNode(DataType d);
//销毁链表
void DestroyLinkList(pList* pplist);
//尾部插入一个元素
void PushBack(pList* pplist, DataType d);
//尾部删除一个元素
void PopBack(pList* pplist);
//头部插人一个元素
void PushFront(pList* pplist, DataType d);
//头部删除一个元素
void PopFront(pList* pplist);
//找一个元素
pNode Find(pList plist, DataType d);

//在指定位置之前插入一个值 
void Insert(pList* pplist, pNode pos, DataType d);
//指定位置删除 
void Erase(pList* pplist, pNode pos);
//删除指定元素
void Remove(pList* pplist, DataType d);
//删除所有指定元素
void RemoveAll(pList* pplist, DataType d);
//打印链表
void PrintLinkList(pList *pplist);
//链表的长度
int GetListLength(pList pplist);

#endif //__LINKLIST_H__ 

LinkList.c

#include "LinkList.h"


//初始化链表
void InitLinkList(pList* pplist)
{
	assert(pplist);
	*pplist = NULL;
}
//创建节点
pNode BuyNode(DataType d)
{
	pNode node = (pNode)malloc(sizeof(Node));
	if (node == NULL)
	{
		return NULL;
	}
	node->data = d;
	node->next = NULL;
	return node;

}

//销毁链表
void DestroyLinkList(pList* pplist)
{
	assert(pplist);
	pNode cur = *pplist;
	while (cur)
	{
		pNode del = cur;
		cur = cur->next;
		free(del);
		del = NULL;
	}
	*pplist = NULL;
}
//尾插
void PushBack(pList* pplist, DataType d)
{
	assert(pplist);
	pNode newNode = BuyNode(d);
	if (newNode == NULL)
	{
		return;
	}
	if (*pplist == NULL)
	{
		*pplist = newNode;
	}
	else
	{
		pNode cur = *pplist;
		while (cur->next)
		{
			cur = cur->next;
		}
		cur->next = newNode;
	}
}
//尾删
void PopBack(pList* pplist)
{
	assert(pplist);
	pNode cur = *pplist;
	if (cur == NULL)
	{
		return;
	}
	if (cur->next == NULL)
	{
		free(cur);
		cur = NULL;
	}
	else
	{
		while (cur->next->next!=NULL)
		{
			cur = cur->next;
		}
		free(cur->next);
		cur->next = NULL;
	}
}
//头插
void PushFront(pList* pplist, DataType d)
{
	assert(pplist);
	pNode newNode = BuyNode(d);
	if (newNode == NULL)
	{
		return;
	}
	newNode->next = *pplist;
	*pplist = newNode;
}
//头删
void PopFront(pList* pplist)
{
	assert(pplist);
	if (*pplist == NULL)
	{
		return;
	}
	else
	{
		pNode cur = *pplist;
		*pplist = cur->next;
		free(cur);
		cur = NULL;
	}
}

//在链表中找一个元素，返回节点的位置
pNode Find(pList plist, DataType d)
{
	pNode cur = plist;
	if (plist == NULL)
	{
		return;
	}
	while (cur)
	{
		if (cur->data == d)
		{
			return cur;
		}
		cur = cur->next;
	}
	return NULL;
}

//在指定位置之前插入一个值 
void Insert(pList* pplist, pNode pos, DataType d)
{
	assert(pplist);
	assert(pos);
	pNode newNode = BuyNode(d);
	if (*pplist == pos)
	{
		//前插
		newNode->next = *pplist;
		*pplist = newNode;
	}
	else
	{
		pNode cur = *pplist;
		while (cur&&cur->next != pos)
		{
			cur = cur->next;
		}
		if (cur != NULL)
		{
			newNode->next = cur->next;
			cur->next = newNode;
		}
	}
}
//指定位置删除 
void Erase(pList* pplist, pNode pos)
{
	assert(pplist);
	assert(pos);
	pNode cur = *pplist;
	if (*pplist == pos)
	{
		*pplist = pos->next;
		free(pos);
		pos = NULL;
	}
	else
	{
		while (cur && cur->next != pos)
		{
			cur = cur->next;
		}
		if (cur != NULL)
		{
			cur->next = pos->next;
			free(pos);
			pos = NULL;
		}
	}
}
//删除指定元素
void Remove(pList* pplist, DataType d)
{
	assert(pplist);
	pNode cur = *pplist;
	pNode pre = *pplist;
	while (cur)
	{
		if (cur->data == d)
		{
			if (*pplist == cur)
			{
				*pplist = cur->next;
				free(cur);
				cur = NULL;
			}
			else
			{
				while (pre&&pre->next != cur)
				{
					pre = pre->next;
				}
				pre->next = cur->next;
				free(cur);
				cur = NULL;
			}
			return;
		}
		cur = cur->next;
	}

	
}
//删除所有指定元素
void RemoveAll(pList* pplist, DataType d)
{
	assert(pplist);
	pNode cur = *pplist;
	pNode pre = *pplist;
	pNode del = NULL;
	while (cur)
	{
		if (cur->data == d)
		{
			if (*pplist == cur)
			{
				*pplist = cur->next;
				free(cur);
				cur = *pplist;
			}
			else
			{
				del = cur;
				pre->next = cur->next;
				cur = cur->next;
				free(del);
				del = NULL;
			}
		}
		else
		{
			pre = cur;
			cur = cur->next;
		}
	}
}

//求链表的长度
int GetListLength(pList plist)
{
	int count = 0;
	pNode cur = plist;
	while (cur)
	{
		count++;
		cur = cur->next;
	}
	return count;
}
//打印链表
void PrintLinkList(pList *pplist)
{
	assert(pplist);
	pNode cur = *pplist;
	while (cur)
	{
		printf("%d ", cur->data);
		cur = cur->next;
	}
	printf("\n");
}

test.c

#include"LinkList.h"

void TestLinklist()
{
	pList plist;
	InitLinkList(&plist);
	PushBack(&plist, 1);
	PushBack(&plist, 1);

	PushBack(&plist, 2);
	PushBack(&plist, 3);
	PushBack(&plist, 4);
	PrintLinkList(&plist);

	PopBack(&plist);
	PrintLinkList(&plist);

	PushFront(&plist, 5);
	PrintLinkList(&plist);

	PopFront(&plist);
	PrintLinkList(&plist);

	Remove(&plist, 2);
	PrintLinkList(&plist);

	RemoveAll(&plist, 1);
	PrintLinkList(&plist);

}

int main()
{
	TestLinklist();
	return 0;
}