【数据结构】_不带头非循环单向链表

1. 链表的概念及结构

2. 链表的分类

3. 单链表的实现

3.1 SList.h头文件

3.2 SList.c源文件

3.3 Test_SList.c测试文件

关于线性表，已介绍顺序表，详见下文：

【数据结构】_顺序表-CSDN博客

本文介绍链表；

基于顺序表的特点，思考改善方案：

按需申请释放空间，不再将数据存储于连续的一整块空间中，而是需要一个数据开辟一个小空间。为了方便访问数据，首先创建一个头指针（头结点）指向存放第一个数据的内存位置处，而在该位置处，除了存储该数据本身，再分配一块空间用于存放下一个数据的地址，直至某位置存放的下一个位置的指针为空则数据截止。

同时，这种存储方式也有效地提高了插入删除数据时的效率，无需再大量挪动数据。

这种数据结构就称为链表。

1. 链表的概念及结构

链表是一种物理存储结构上非连续、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。

链表在逻辑上是连续的，在物理上不是连续的；

2. 链表的分类

单向和双向：

带头和不带头：

循环和非循环：

最常用的链表结构是：无头单向非循环链表和带头双向循环链表：

3. 单链表的实现

3.1 SList.h头文件

#pragma once
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>// 链表结点
typedef int SLTDataType;
typedef struct SListNode {SLTDataType data;struct SListNode* next;
}SLTNode;
void SLTPrint(SLTNode* phead);
void SLTPushBack(SLTNode** pphead, SLTDataType x);
void SLTPushFront(SLTNode** pphead, SLTDataType x);
void SLTPopBack(SLTNode** pphead);
void SLTPopFront(SLTNode** pphead);
SLTNode* SLTCreatNode(SLTDataType x);
SLTNode* SLTFind(SLTNode* phead, SLTDataType x);
// 在指定位置前插入数据
void SLTInsert(SLTNode** pphead, SLTNode* pos, SLTDataType x);
// 在指定位置后插入数据
void SLTInsertAfter(SLTNode* pos, SLTDataType x);
// 删除pos结点
void SLTErase(SLTNode** pphead, SLTNode* pos);
// 删除pos后的结点
void SLTEraseAfter(SLTNode* pos);
// 销毁
void SLTDestory(SLTNode** pphead);

3.2 SList.c源文件

#include"SList.h"
void SLTPrint(SLTNode* phead) {SLTNode* pcur = phead;while (pcur) {printf("%d-> ", pcur->data);pcur = pcur->next;}printf("NULL\n");
}
SLTNode* SLTCreatNode(SLTDataType x) {SLTNode* newNode = (SLTNode*)malloc(sizeof(SLTNode));if (newNode == NULL) {perror("malloc fail\n");exit(1);}newNode->data = x;newNode->next = NULL;return newNode;
}
void SLTPushBack(SLTNode** pphead, SLTDataType x) {assert(pphead);SLTNode* newNode = SLTCreatNode(x);// 空链表if (*pphead == NULL) {*pphead = newNode;}else {// 非空链表SLTNode* curNode = *pphead;while (curNode->next) {curNode = curNode->next;}curNode->next = newNode;}
}
void SLTPushFront(SLTNode** pphead, SLTDataType x) {assert(pphead);SLTNode* newNode = SLTCreatNode(x);newNode->next = *pphead;// 令新结点为链表的头结点*pphead = newNode;
}
void SLTPopBack(SLTNode** pphead) {assert(pphead && *pphead);// 链表只有一个结点if ((*pphead)->next == NULL) {free(*pphead);*pphead = NULL;}// 链表有多个结点else {SLTNode* tailPrevNode = *pphead;SLTNode* tailNode = *pphead;while (tailNode->next) {tailPrevNode = tailNode;tailNode = tailNode->next;}free(tailNode);tailNode = NULL;tailPrevNode->next = NULL;}
}
void SLTPopFront(SLTNode** pphead) {assert(pphead && *pphead);SLTNode* secNode = (*pphead)->next;free(*pphead);*pphead = secNode;
}
SLTNode* SLTFind(SLTNode* phead, SLTDataType x) {SLTNode* curNode = phead;while (curNode) {if (curNode->data == x) {return curNode;}curNode = curNode->next;}return NULL;
}
// 在指定位置前插入数据
void SLTInsert(SLTNode** pphead, SLTNode* pos, SLTDataType x) {assert(pphead && *pphead && pos);SLTNode* newNode = SLTCreatNode(x);if (pos == *pphead) {// 调用头插方法SLTPushFront(pphead, x);}else {SLTNode* posPrevNode = *pphead;while (posPrevNode->next != pos) {posPrevNode = posPrevNode->next;}posPrevNode->next = newNode;newNode->next = pos;}
}
// 在指定位置后插入数据
void SLTInsertAfter(SLTNode* pos, SLTDataType x) {assert(pos);SLTNode* newNode = SLTCreatNode(x);SLTNode* posAfterNode = pos->next;pos->next = newNode;newNode->next = posAfterNode;
}
// 删除pos结点
void SLTErase(SLTNode** pphead, SLTNode* pos) {assert(pphead && *pphead && pos);if (*pphead == pos) {// 调用头删方法SLTPopFront(pphead);}else {SLTNode* posPrevNode = *pphead;while (posPrevNode->next != pos) {posPrevNode = posPrevNode->next;}posPrevNode->next = pos->next;free(pos);pos = NULL;}
}
// 删除pos后的结点
void SLTEraseAfter(SLTNode* pos) {assert(pos && pos->next);SLTNode* posAfterNode = pos->next;pos->next = posAfterNode->next;free(posAfterNode);posAfterNode = NULL;
}
// 销毁
void SLTDestory(SLTNode** pphead) {assert(pphead && *pphead);SLTNode* curNode = *pphead;while (curNode) {SLTNode* curNextNode= curNode->next;free(curNode);curNode = NULL;}*pphead = NULL;
}

3.3 Test_SList.c测试文件

#include"SList.h"
void Test11() {SLTNode* plist = NULL;SLTPushBack(&plist, 1);SLTPushBack(&plist, 2);SLTPushBack(&plist, 3);SLTPushBack(&plist, 4);SLTPrint(plist);SLTDestory(&plist);SLTPrint(plist);
}
void Test10() {SLTNode* plist = NULL;SLTPushBack(&plist, 1);SLTPushBack(&plist, 2);SLTPushBack(&plist, 3);SLTPushBack(&plist, 4);SLTPrint(plist);SLTNode* aimNode1 = SLTFind(plist, 3);SLTEraseAfter(aimNode1);SLTPrint(plist);SLTNode* aimNode2 = SLTFind(plist, 1);SLTEraseAfter(aimNode2);SLTPrint(plist);
}
void Test9() {SLTNode* plist = NULL;SLTPushBack(&plist, 1);SLTPushBack(&plist, 2);SLTPushBack(&plist, 3);SLTPushBack(&plist, 4);SLTPrint(plist);SLTNode* aimNode1 = SLTFind(plist, 3);SLTErase(&plist, aimNode1);SLTPrint(plist);SLTNode* aimNode2 = SLTFind(plist, 1);SLTErase(&plist, aimNode2);SLTPrint(plist);
}
void Test8() {SLTNode* plist = NULL;SLTPushBack(&plist, 1);SLTPushBack(&plist, 2);SLTPushBack(&plist, 3);SLTPushBack(&plist, 4);SLTPrint(plist);SLTNode* aimNode1 = SLTFind(plist, 3);SLTInsertAfter(aimNode1, 85);SLTPrint(plist);SLTNode* aimNode2 = SLTFind(plist, 1);SLTInsertAfter(aimNode2, 97);SLTPrint(plist);
}
void Test7(){SLTNode* plist = NULL;SLTPushBack(&plist, 1);SLTPushBack(&plist, 2);SLTPushBack(&plist, 3);SLTPushBack(&plist, 4);SLTPrint(plist);SLTNode* aimNode1 = SLTFind(plist, 3);SLTInsert(&plist, aimNode1, 85);SLTPrint(plist);SLTNode* aimNode2 = SLTFind(plist, 1);SLTInsert(&plist, aimNode2, 97);SLTPrint(plist);
}
void Test6() {SLTNode* plist = NULL;SLTPushBack(&plist, 1);SLTPushBack(&plist, 2);SLTPushBack(&plist, 3);SLTPushBack(&plist, 4);SLTPrint(plist);// SLTNode* aimNode = SLTFind(plist, 3);SLTNode* aimNode = SLTFind(plist, 6);if (aimNode == NULL)printf("Find nothing\n");elseprintf("Find successfully\n");
}
void Test5() {SLTNode* plist = NULL;SLTPushBack(&plist, 1);SLTPushBack(&plist, 2);SLTPushBack(&plist, 3);SLTPrint(plist);SLTPopFront(&plist);SLTPrint(plist);SLTPopFront(&plist);SLTPrint(plist);SLTPopFront(&plist);SLTPrint(plist);
}
void Test4() {SLTNode* plist = NULL;SLTPushBack(&plist, 1);SLTPushBack(&plist, 2);SLTPushBack(&plist, 3);SLTPrint(plist);SLTPopBack(&plist);SLTPrint(plist);SLTPopBack(&plist);SLTPrint(plist);SLTPopBack(&plist);SLTPrint(plist);
}
void Test3() {SLTNode* plist = NULL;SLTPushFront(&plist, 1);SLTPushFront(&plist, 2);SLTPushFront(&plist, 3);SLTPushFront(&plist, 4);SLTPrint(plist);
}
void Test2() {SLTNode* plist = NULL;SLTPushBack(&plist, 1);SLTPushBack(&plist, 2);SLTPushBack(&plist, 3);SLTPushBack(&plist, 4);SLTPrint(plist);
}void Test1() {SLTNode* node1 = (SLTNode*)malloc(sizeof(SLTNode));node1->data = 1;SLTNode* node2 = (SLTNode*)malloc(sizeof(SLTNode));node2->data = 2;SLTNode* node3 = (SLTNode*)malloc(sizeof(SLTNode));node3->data = 3;SLTNode* node4 = (SLTNode*)malloc(sizeof(SLTNode));node4->data = 4;node1->next = node2;node2->next = node3;node3->next = node4;node4->next = NULL;SLTNode* plist = node1;SLTPrint(plist);
}
int main() {//Test1();//Test2();//Test3();//Test4();//Test5();//Test6();//Test7();//Test8();//Test9();//Test10();Test11();return 0;
}