链表基本接口实现

list.h

#ifndef __LIST_H__
#define __LIST_H__

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

typedef int DataType;

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


void InitList(pList* pplist);//初始化链表
pNode BuyNode(DataType d);//申请新结点
void PushBack(pList* pplist, DataType d);//尾插
void PrintList(pList plist);//打印链表
void DestoryList(pList* pplist);//销毁链表
int GetListLength(pList plist);//得到链表的长度
void PopBack(pList* pplist);//尾删
void PushFront(pList* pplist, DataType d);//尾插
void PopFront(pList* pplist);//头删
pNode Find(pList plist, DataType d);//查找指定元素
void Insert(pList* pplist, pNode pos, DataType d);//指定位置之前插入指定值
void Erase(pList* pplist, pNode pos);//删除指定位置的结点
void Remove(pList* pplist, DataType d);//删除链表中出现的第一个指定元素
void RemoveAll(pList* pplist, DataType d);//删除链表中出现的所有指定元素

#endif//__LIST_H__

list.c

#define _CRT_SECURE_NO_WARNINGS

#include "list.h"

void InitList(pList* pplist)
{
	assert(pplist != NULL);
	*pplist = NULL;
}

pNode BuyNode(DataType d)
{
	pNode newNode = (pNode)malloc(sizeof(Node));
	newNode->data = d;
	newNode->next = NULL;
	return newNode;
}

void DestoryList(pList* pplist)
{
	assert(pplist);
	pNode cur = *pplist;//cur指向第一个结点
	while (cur)
	{
		pNode del = cur;
		cur = cur->next;
		free(del);
		del = NULL;
	}
	*pplist = NULL;//
}

void PushBack(pList* pplist, DataType d)
{
	pNode newNode = BuyNode(d);
	//assert
	assert(pplist);
	//有无元素
	if (*pplist == NULL)
	{
		pNode newNode = BuyNode(d);
		*pplist = newNode;
	}
	//有元素找尾（next指向空）
	else
	{
		pNode cur = *pplist;
		pNode newNode = BuyNode(d);
		while (cur->next != NULL)
		{
			cur = cur->next;
		}
		cur->next = newNode;
	}
}

void PrintList(pList plist)
{
	//无需断言plist,当plist为空时，表明这是一个空链表，也是合法的
	pNode cur = plist;
	while (cur != NULL)
	{
		printf("%d-->", cur->data);
		cur = cur->next;
	}
	printf("Over\n");
}

int GetListLength(pList plist)
{
	pNode cur = plist;
	int count = 0;
	while (cur)
	{
		count++;
		cur = cur->next;
	}
	return count;
}

void PopBack(pList* pplist)
{
	assert(pplist);
	//空链表
	if (*pplist == NULL)
	{
		return;
	}
	//一个节点
	if ((*pplist)->next == NULL)
	{
		free(*pplist);
		*pplist = NULL;
		return;
	}
	//多个节点
	else
	{
		pNode cur = *pplist;
		while (cur->next->next != NULL)
		{
			cur = cur->next;
		}
		free(cur->next);
		cur->next = NULL;
	}
}

void PushFront(pList* pplist, DataType d)
{
	assert(pplist);
	pNode newNode = BuyNode(d);
	newNode->next = *pplist;
	*pplist = newNode;
}

void PopFront(pList* pplist)
{
	//assert
	assert(pplist);
	//没有节点
	if (*pplist == NULL)
	{
		printf("链表为空不能头删\n");
	}
	//有节点
	else
	{
		pNode cur = *pplist;
		*pplist = cur->next;
		free(cur);
		cur = NULL;
	}
}

pNode Find(pList plist, DataType d)
{
	pNode cur = plist;
	while (cur)
	{
		if (cur->data == d)
		{
			return cur;
		}
		cur = cur->next;
	}
	return NULL;
}

void Insert(pList*pplist, pNode pos, DataType d)
{
	pNode newNode = NULL;
	//assert
	assert(pplist);
	assert(*pplist);
	assert(pos);
	//pos指向第一个结点采用头插
	if (pos == *pplist)
	{
		newNode = BuyNode(d);
		newNode->next = *pplist;
		*pplist = newNode;
	}
	//pos不是第一个节点：pos合法，pos不合法
	else
	{
		pNode cur = *pplist;
		while (cur&&cur->next != pos)
		{
			cur = cur->next;
		}
		if (cur)
		{
			newNode = BuyNode(d);
			cur->next = newNode;
			newNode->next = pos;
		}
		
	}
}

void Erase(pList* pplist, pNode pos)
{
	assert(pplist);
	assert(pos);
	//判空
	if (*pplist == NULL)//
	{
		return;
	}
	//pos是指向第一个结点，头删
	if (*pplist == pos)
	{
		//头删
		pNode del = pos;
		*pplist = (*pplist)->next;
		free(del);
		del = NULL;
	}
	//pos不是第一个结点：pos合法，pos不合法
	else
	{
		pNode cur = *pplist;
		while (cur&&cur->next != pos)
		{
			cur = cur->next;
		}
		if (cur)
		{
			cur->next = pos->next;
			free(pos);
			pos = NULL;
		}
	}
}

void Remove(pList* pplist, DataType d)
{
	pNode cur = NULL;
	pNode prev = NULL;
	assert(pplist);
	assert(*pplist);
	cur = *pplist;
	while (cur)
	{
		if (cur->data == d)
		{
			//是第一个结点
			if (*pplist == cur)
			{
				PopFront(pplist);
			}
			//不是第一个结点
			else
			{
				prev->next = cur->next;
				free(cur);
				cur = NULL;
			}
			return;
		}
		else
		{
			prev = cur;
			cur = cur->next;
		}
	}
}

void RemoveAll(pList* pplist, DataType d)
{
	pNode cur = NULL;
	pNode prev = NULL;
	assert(pplist);
	assert(*pplist);
	cur = *pplist;
	while (cur)
	{
		if (cur->data == d)
		{
			//是第一个结点
			if (*pplist == cur)
			{
				PopFront(pplist);
				cur = *pplist;
			}
			//不是第一个结点
			else
			{
				prev->next = cur->next;
				free(cur);
				cur = prev;
			}
		}
		else
		{
			prev = cur;
			cur = cur->next;
		}
	}
}

test.c

#define _CRT_SECURE_NO_WARNINGS
#include "list.h"

void test()
{
	Node* plist = NULL;//pList plist = NULL;
	InitList(&plist);
	PushBack(&plist, 1);
	PushBack(&plist, 2);
	PushBack(&plist, 3);
	PushBack(&plist, 4);
	PrintList(plist);
	printf("链表的长度是：%d\n", GetListLength(plist));
	DestoryList(&plist);
	printf("链表的长度是：%d\n", GetListLength(plist));
	PrintList(plist);
}

void TestPopBack()
{
	Node* plist = NULL;//pList plist = NULL;
	//InitList(&plist);
	PushBack(&plist, 1);
	PushBack(&plist, 2);
	PushBack(&plist, 3);
	PushBack(&plist, 4);
	PrintList(plist);
	PopBack(&plist);
	PrintList(plist);//1 2 3
	DestoryList(&plist);
}

void TestPushFront()
{
	Node* plist = NULL;
	PushFront(&plist, 1);
	PushFront(&plist, 2);
	PushFront(&plist, 3);
	PushFront(&plist, 4);
	PrintList(plist);//4 3 2 1
	PopFront(&plist);
	PrintList(plist);//3 2 1
	PopFront(&plist);
	PrintList(plist);//2 1
	DestoryList(&plist);
}

void TestFind()
{
	Node* plist = NULL;
	pNode pos = NULL;
	PushFront(&plist, 1);
	PushFront(&plist, 2);
	PushFront(&plist, 3);
	PushFront(&plist, 4);
	PrintList(plist);//4 3 2 1
	pos = Find(plist, 3);
	if (pos)
	{
		printf("%d\n", pos->data);
	}
	DestoryList(&plist);
}

void TestInsert()
{
	Node* plist = NULL;
	pNode pos = NULL;
	PushFront(&plist, 1);
	PushFront(&plist, 2);
	PushFront(&plist, 3);
	PushFront(&plist, 4);
	PrintList(plist);//4 3 2 1
	pos = Find(plist, 1);
	if (pos)
	{
		Insert(&plist, pos, 5);
	}
	PrintList(plist);
	DestoryList(&plist);
}

void TestErase()
{
	Node* plist = NULL;
	pNode pos = NULL;
	PushFront(&plist, 1);
	PushFront(&plist, 2);
	PushFront(&plist, 3);
	PushFront(&plist, 4);
	PrintList(plist);//4 3 2 1
	pos = Find(plist, 1);
	if (pos)
	{
		Erase(&plist, pos);
	}
	PrintList(plist);
	DestoryList(&plist);
}

void TestRemove()
{
	Node* plist = NULL;
	pNode pos = NULL;
	PushFront(&plist, 1);
	PushFront(&plist, 2);
	PushFront(&plist, 3);
	PushFront(&plist, 2);
	PushFront(&plist, 4);
	PrintList(plist);
	Remove(&plist, 2);
	PrintList(plist);
}

void TestRemoveAll()
{
	Node* plist = NULL;
	pNode pos = NULL;
	PushFront(&plist, 1);
	PushFront(&plist, 2);
	PushFront(&plist, 3);
	PushFront(&plist, 2);
	PushFront(&plist, 4);
	PrintList(plist);
	RemoveAll(&plist, 2);
	PrintList(plist);
}

int main(void)
{
	//test();
	//TestPopBack();
	//TestPushFront();
	//TestFind();
	//TestInsert();
	//TestErase();
	//TestRemove();
	TestRemoveAll();
	system("pause");
	return 0;
}