数据结构——单链表的实现

不带头不循环的单向链表

#pragma once

#include 
#include 

typedef int SLDataType;

struct SListNode
{
	SLDataType data;
	struct SListNode* next;
};
typedef struct SListNode SLTNode;

//不会改变链表的头指针，传一级指针
void SListPrint(SLTNode* phead);
//可能会改变链表的头指针，传二级指针
void SListPushBack(SLTNode** pphead, SLDataType x);
void SListPushFront(SLTNode** pphead, SLDataType x);
void SListPopFront(SLTNode** pphead);
void SListPopBack(SLTNode** pphead);

SLTNode* SListFind(SLTNode* phead, SLDataType x);
//在pos的前面插入x
void SListInsert(SLTNode** pphead, SLTNode* pos, SLDataType x);
//删除pos位置的值
void SListErase(SLTNode** pphead, SLTNode* pos);

有些地方是这样的
在pos前面插入x
//void SListInsert(SLTNode** pphead, int i, SLDataType x);
删除pos位置的值
//void SLTErase(SLTNode** pphead, int i);

#include "SList.h"

void SListPrint(SLTNode* phead)
{
	SLTNode* cur = phead;
	while (cur != NULL)
	{
		printf("%d->", cur->data);
		cur = cur->next;
	}
	printf("NULLn");
}

SLTNode* BuySLTNode(SLDataType x)
{
	SLTNode* newnode = (SLTNode*)malloc(sizeof(SLTNode));
	newnode->data = x;
	newnode->next = NULL;
	return newnode;
}

void SListPushBack(SLTNode** pphead, SLDataType x)
{
	SLTNode* newnode = BuySLTNode(x);
	if (*pphead == NULL)
	{
		*pphead = newnode;
	}
	else
	{
		//找尾结点的指针
		SLTNode* tail = *pphead;
		while (tail->next != NULL)
		{
			tail->next;
		}
		tail->next = newnode;
	}
}

void SListPushFront(SLTNode** pphead, SLDataType x)
{
	SLTNode* newnode = BuySLTNode(x);
	newnode->next = *pphead;
	*pphead = newnode;
}

void SListPopFront(SLTNode** pphead)
{
	SLTNode* next = (*pphead)->next;
	free(*pphead);
	*pphead = NULL;
}

void SListPopBack(SLTNode** pphead)
{
	//1.空
	//2.一个节点
	//3.一个节点以上
	if (*pphead == NULL)
	{
		return;
	}
	else if ((*pphead)->next == NULL)
	{
		free(*pphead);
		*pphead = NULL;
	}
	else
	{
		SLTNode* prev = NULL;
		SLTNode* tail = *pphead;
		while (tail->next != NULL)
		{
			prev = tail;
			tail = tail->next;
		}
		free(tail);
		prev->next = NULL;
	}
}

SLTNode* SListFind(SLTNode* phead, SLDataType x)
{
	SLTNode* cur = phead;
	while (cur != NULL)
	{
		if (cur->data == x)
		{
			return cur;
		}
	}
	return NULL;
}

//在pos的前面插入x
void SListInsert(SLTNode** pphead, SLTNode* pos, SLDataType x)
{
	if (pos == *pphead)
	{
		SListPushFront(pphead, x);
	}
	else
	{
		SLTNode* newnode = BuySLTNode(x);
		SLTNode* prev = *pphead;
		while (prev->next != pos)
		{
			prev->next = newnode;
			newnode->next = pos;
		}
	}
}

//删除pos位置的值
void SListErase(SLTNode** pphead, SLTNode* pos)
{
	if (pos == *pphead)
	{
		SListPopFront(pphead);
	}
	else
	{
		SLTNode* prev = *pphead;
		while (prev->next != pos)
		{
			prev = prev->next;
		}
		prev->next = pos->next;
		free(pos);
	}
}

#define _CRT_SECURE_NO_WARNINGS 1

#include "SList.h"

void TestList1()
{
	SLTNode* plist = NULL;
	SListPushBack(&plist, 1);
	SListPushBack(&plist, 2);
	SListPushBack(&plist, 3);
	SListPushBack(&plist, 4);
	SListPushBack(&plist, 5);
	SListPrint(plist);
}
int main()
{
	TestList1();
}