可直接获取链表长度的单链表

可直接获取链表长度的单链表

SeqList.h文件

#pragma once
//存size的链表
#include<stdio.h>
#include<assert.h>
#include<stdbool.h>
#include<stdlib.h>

typedef int SeqDataType;

typedef struct SeqNode
{
	struct SeqNode* next;
	SeqDataType val;
}Node;

typedef struct SeqList
{
	Node* head;
	int sz;
}List;

Node* Buy_Node(SeqDataType x);

void Init(List* phead);
void Push_back(List* phead, SeqDataType x);
void Push_front(List* phead, SeqDataType x);
void Pop_back(List* phead);
void Pop_Front(List* phead);
void Print(List* phead);
void Destroy(List* phead);
void insert_pos(List* phead, Node* pos, SeqDataType x);
void erase_pos(List* phead, Node* pos);
int get_size(List* phead);
bool is_Empty(List* phead);
Node* find(List* phead,SeqDataType x);

SeqList.c文件

#include"SeqList.h"

void Init(List* phead) //初始化头结点和元素个数
{
	phead->head = NULL; //头指针指向NULL
	phead->sz = 0; //元素个数为0
}

Node* Buy_Node(SeqDataType x) //创建新节点
{
	Node* newnode = (Node*)malloc(sizeof(Node));
	if (newnode == NULL) //判断内存是否开辟成功
	{
		perror("malloc fail:"); //输出错误信息
		exit(-1);
	}
	newnode->next = NULL; //新节点的next指向NULL
	newnode->val = x; //新节点的值为x
	return newnode; //返回新节点
}

void Push_back(List* phead, SeqDataType x) //尾插法
{
	assert(phead);
	Node* newnode = Buy_Node(x);
	Node* cur = phead->head;
	if (cur == NULL) //如果是第一个节点
	{
		phead->head = newnode;
	}
	else
	{
		while (cur->next != NULL) //找尾节点
		{
			cur = cur->next;
		} cur->next = newnode; //尾节点的next指向新节点
	} phead->sz++; //元素个数+1
}

void Print(List* phead) //打印链表
{
	Node* cur = (phead->head);
	while (cur != NULL)
	{
		printf("%d", cur->val);
		cur = cur->next;
		if (cur != NULL)
		{
			printf("->");
		}
	} printf("\n");
}

void Destroy(List* phead) //销毁链表
{
	assert(phead);
	Node* cur = phead->head;
	while (cur != NULL)
	{
		Node* next = cur->next;
		free(cur);
		cur = next;
	} phead->head = NULL;
	phead->sz = 0;
}

int get_size(List* phead) //获取链表大小
{
	return phead->sz;
}

bool is_Empty(List* phead) //判断链表是否为空
{
	return phead->sz == 0;
}

void Push_front(List* phead, SeqDataType x) //头插法
{
	Node* newnode = Buy_Node(x);
	if (phead->head == NULL) //链表为空,新节点为头节点
	{
		phead->head = newnode;
	}
	else
	{
		Node** first = &phead->head; //保存头指针地址的指针first
		newnode->next = *first; //新节点的next指向原头节点
		*first = newnode; //first指向新节点,新节点成为头节点
	}
}

void Pop_back(List* phead) //尾部删除
{
	assert(phead);
	assert(!is_Empty(phead)); //不能再删了
	Node* cur = phead->head;
	if (cur->next == NULL) //只有一个节点,直接释放
	{
		free(phead->head);
		phead->head = NULL;
	}
	else
	{
		Node* prev = phead->head;
		while (cur->next != NULL) //找尾节点的前一个节点
		{
			prev = cur;
			cur = cur->next;
		}
		free(cur); //释放尾节点
		cur = NULL;
		prev->next = NULL; //尾节点的前一个节点的next指向NULL
	}
}

void Pop_Front(List* phead) //头部删除
{
	assert(phead != NULL);
	assert(!is_Empty(phead));
	Node* next = phead->head->next; //保存头节点的next
	if (next == NULL) //只有一个节点,直接释放
	{
		free(phead->head);
		phead->head = NULL;
	}
	else
	{
		free(phead->head);
		phead->head = next; //头指针指向原下一节点,实现删除头节点
	}
}

Node* find(List* phead, SeqDataType x) //查找值为x的节点
{
	Node* cur = phead->head;
	while (cur != NULL)
	{
		if (cur->val == x) //找到节点
		{
			return cur;
		}
		cur = cur->next; //继续向后找
	}
	return NULL; //找不到
}

//在pos位置之后插入
void insert_pos(List* phead, Node* pos, SeqDataType x)
{
	assert(phead);
	assert(pos);
	if (phead->head == pos) //在第一个节点之后插入
	{
		Push_front(phead, x);
	}
	else
	{
		Node* newnode = Buy_Node(x); //创建新节点
		Node* next = pos->next;
		pos->next = newnode; //新节点插入到pos节点之后
		newnode->next = next;
	} phead->sz++;
}

//在pos位置之后删除
void erase_pos(List* phead, Node* pos)
{
	assert(phead);
	assert(pos);
	Node* next = pos->next;
	if (pos == phead->head) //删除第一个节点
	{
		phead->head = next;
		free(pos);
		pos = NULL;
		if (phead->head == NULL) //链表只有一个节点,释放
		{
			free(phead->head);
			phead->head = NULL;
		}
	}
	else
	{
		Node* prev = phead->head;
		while (prev->next != pos) //找pos前一个节点
		{
			prev = prev->next;
		}
		prev->next = next; //前一个节点的next指向pos的next
		free(pos);
		pos = NULL;
	}
	phead->sz--;
}

test.c文件

#include"SeqList.h"

int main(void)
{
	List phead;
	Init(&phead);
	Push_back(&phead, 1);
	Push_back(&phead, 2);
	Push_back(&phead, 3);
	Push_back(&phead, 4);
	Push_back(&phead, 5);
	Push_back(&phead, 8);
	Push_back(&phead, 10);
	Print(&phead);
	Push_front(&phead, 6);
	Print(&phead);
	puts("");
	printf("sz= %d\n", get_size(&phead));
	Node* find_node = find(&phead, 5);
	insert_pos(&phead, find_node, 100);
	Print(&phead);
	Node* find_node1 = find(&phead, 6);
	insert_pos(&phead, find_node1, 123);
	Print(&phead);
	erase_pos(&phead, find_node);
	Print(&phead);
	erase_pos(&phead, find_node1);
	Print(&phead);
	Node* find_node2 = find(&phead, 123);
	Node* find_node3 = find(&phead, 10);
	erase_pos(&phead, find_node2);
	Print(&phead);
	erase_pos(&phead, find_node3);
	Print(&phead);

	return 0;
}