【数据结构】C语言实现双向链表（带头尾指针，非循环链表）

DLinkList.h

#pragma once

#include
#include


typedef char DLinkType;

//C语言双向链表

typedef struct DLinkNode{

	 DLinkType data;
	 struct DLinkNode* _next;
	 struct DLinkNode* _prev;

}DLinkNode;

typedef struct DLinkList{

	DLinkNode* head;
	DLinkNode* tail;
	int size;

}DLinkList;

//创建一个结点
DLinkNode* CreatNewNode(DLinkType value);
//释放一个结点
void DestoryNode(DLinkNode** node);
//初始化双向链表
DLinkList* InitDLinkList();
//判断链表是否为空
int DLinkListEmpty(DLinkList* plist);
//尾插一个元素
DLinkList* DLinkListPushBack(DLinkList* plist, DLinkType value);
//打印整个链表
void PrintChar(DLinkList* plist, char* msg);
//尾删一个元素
void DLinkListPopBack(DLinkList* plist);
//头插一个元素
void DLinkListPushFront(DLinkList* plist, DLinkType value);
//头删一个元素
void DLinkListPopFront(DLinkList* plist);
//查找某个元素
DLinkNode* DLinkListFind(DLinkList* plist, DLinkType to_find);
//往指定位置之前插入一个元素
void DLinkListInsert(DLinkList* plist,DLinkNode* pos, DLinkType value);
//往指定位置之后插入一个元素
void DLinkListInsertAfter(DLinkList* plist, DLinkNode* pos, DLinkType value);
//删除指定位置的元素
void DLinkListErase(DLinkList* plist, DLinkNode* pos);
//删除指定值的元素
void DLinkListRemove(DLinkList* plist, DLinkType to_delete);
//删除所有指定值的元素
void DLinkListRemoveAll(DLinkList* plist, DLinkType to_delete);

//删除一个链表的所有元素
void DLinkListClear(DLinkList* plist);

DLinkList.c

#define _CRT_SECURE_NO_WARNINGS 1

#include"DLinkList.h"

//创建一个结点
DLinkNode* CreatNewNode(DLinkType value) {

	DLinkNode* Node = (DLinkNode*)malloc(sizeof(DLinkNode));
	if (Node != NULL) {

		Node->data = value;
		Node->_next = NULL;
		Node->_prev = NULL;

	}

	return Node;
}

//释放一个结点
void DestoryNode(DLinkNode** node) {

	if (node == NULL) {
		//非法输入
		return;
	}
	if (*node == NULL) {
		//结点传入错误
		return;
	}
	free(*node);
	*node = NULL;

}

//初始化双向链表
DLinkList* InitDLinkList() {

	DLinkList* plist = (DLinkList*)malloc(sizeof(DLinkList));
	plist->head = CreatNewNode('0');

	if (plist != NULL) {

		if (plist->head != NULL) {

			plist->head = plist->head;
			plist->tail = plist->head;
			plist->size = 0;

		}
		else {
			return NULL;
		}
	}
	return plist;
}

//判断链表是否为空
int DLinkListEmpty(DLinkList* plist) {

	if (plist == NULL) {
		return;
	}
	if (plist->tail == plist->head &&
		plist->size == 0) {

		return 1;

	}
	return 0;

}
//尾插一个元素
DLinkList* DLinkListPushBack(DLinkList* plist, DLinkType value) {

	if (plist->head == NULL) {
		return;
	}
	DLinkNode* InsertNode = CreatNewNode(value);
	DLinkNode* cur = plist->head;
	//遍历链表，cur到最后尾指针位置
	while (cur != plist->tail) {

		cur = cur->_next;

	}
	cur->_next = InsertNode;
	InsertNode->_prev = cur;

	plist->tail = InsertNode;

	plist->size++;
	return InsertNode;
}

//打印整个链表
void PrintChar(DLinkList* plist, char* msg) {

	if (plist == NULL) {
		return;
	}
	printf("%s\n", msg);
	DLinkNode* cur1 = plist->head->_next;

	DLinkNode* cur2 = plist->tail;
	if (cur1 == NULL || cur2->_prev == plist->head) {
		//空链表
		printf("\n\n[head]<-[tail]\n\n");
		return;
	}
	//正着打印
	printf("\n\n\n[head]->");
	for (; cur1 != plist->tail; cur1 = cur1->_next) {

		printf("[%c]->", cur1->data);

	}
	printf("[%c]<-[tail]", cur1->data);
	//反着打印
	printf("\n\n\n[tail]->");
	for (; cur2 != plist->head; cur2 = cur2->_prev) {
		printf("[%c]->", cur2->data);
	}
	printf("[head]\n\n\n");
}

//尾删一个元素
void DLinkListPopBack(DLinkList* plist) {

	if (plist == NULL) {
		return;
	}
	DLinkNode* cur = plist->head;
	while (cur->_next != plist->tail) {

		cur = cur->_next;

	}
	DLinkNode* Delete = cur->_next;
	plist->tail = cur;

	Delete->_prev = NULL;
	cur->_next = NULL;
	
	plist->size--;

	DestoryNode(&Delete);
}

//头插一个元素
void DLinkListPushFront(DLinkList* plist, DLinkType value) {

	if (plist == NULL) {
		return;
	}
	DLinkNode* node = CreatNewNode(value);
	DLinkNode* cur = plist->head->_next;

	plist->head->_next = node;
	node->_prev = plist->head;

	node->_next = cur;
	cur->_prev = node;

	plist->size++;

}

//头删一个元素
void DLinkListPopFront(DLinkList* plist) {

	if (plist == NULL) {
		return;
	}
	//保存要删除的元素
	DLinkNode* Delete = plist->head->_next;
	DLinkNode* cur = plist->head->_next->_next;

	plist->head->_next = cur;
	cur->_prev = plist->head;

	plist->size--;
	DestoryNode(&Delete);
}

//查找某个元素
DLinkNode* DLinkListFind(DLinkList* plist, DLinkType to_find) {

	if (plist == NULL) {
		return;
	}
	DLinkNode* cur = plist->head;

	while (cur != plist->tail) {

		cur = cur->_next;
		if (cur->data == to_find) {
			//如果找到第一个值相等的元素，就返回cur
			return cur;
			
		}
	}
	//如果查找失败了，记得释放结点
	DLinkNode* error = CreatNewNode('-1');
	printf("链表里未保存此元素");
	return error;

}

//往指定位置之前插入一个元素
void DLinkListInsert(DLinkList* plist,DLinkNode* pos, DLinkType value) {

	if (pos == NULL) {
		return;
	}
	DLinkNode* cur = CreatNewNode(pos->data);
	DLinkNode* pos_next = pos->_next;
	//判断pos是否是最后一个元素
	if (pos_next == NULL) {

		pos->_next = cur;
		cur->_prev = pos;

		pos->data = value;

		plist->tail = cur;

		plist->size++;
	}
	else{
		pos->_next = cur;
		cur->_prev = pos;

		cur->_next = pos_next;
		pos_next->_prev = cur;

		pos->data = value;
		plist->size++;
	}
}

//往指定位置之后插入一个元素
void DLinkListInsertAfter(DLinkList* plist,DLinkNode* pos, DLinkType value) {

	if (plist == NULL) {
		return;
	}
	//创建新结点
	DLinkNode* insert = CreatNewNode(value);
	DLinkNode* pos_next = pos->_next;

	if (pos_next == NULL) {
		//当前结点是最后一个结点
		pos->_next  = insert;
		insert->_prev = pos;

		//更新尾指针和链表长度size
		plist->size++;
		plist->tail = insert;
	}
	else {
		//交换
		pos->_next = insert;
		insert->_prev = pos;

		insert->_next = pos_next;
		pos_next->_prev = insert;
		//更新链表长度size
		plist->size++;
	}
}

//删除指定位置的元素
void DLinkListErase(DLinkList* plist, DLinkNode* pos) {

	if (plist == NULL) {
		return;
	}
	DLinkNode* cur = plist->head;
	while (cur->_next != pos) {

		cur = cur->_next;
		if (cur->_next == NULL) {
			printf("pos位置传入错误");
			return;
		}

	}
	DLinkNode* Delete = pos;
	DLinkNode* pos_next = pos->_next;

	if (pos_next == NULL) {
		//pos为最后一个元素
		cur->_next = NULL;
		
		//更新链表size，释放删除的结点的空间
		plist->tail = cur;
		plist->size--;
		DestoryNode(&pos);

	}
	else{

		//开始拆除结点
		cur->_next = pos_next;
		pos_next->_prev = cur;

		plist->size--;
		DestoryNode(&pos);

	}
}

//删除指定值的元素
void DLinkListRemove(DLinkList* plist, DLinkType to_delete) {

	if (plist == NULL) {
		return;
	}
	DLinkNode* cur = plist->head;
	while (cur->_next->data != to_delete) {

		cur = cur->_next;
		if (cur->_next == NULL) {
			printf("链表中查不到此元素\n");
			return;
		}
	
	}
	DLinkNode* del_next = cur->_next->_next;
	DLinkNode* Delete = cur->_next;
	if (del_next == NULL) {
		//假如要删除的元素位于链表的最后一位，那么de_next一定为空指针
		cur->_next = NULL;

		//更新尾指针，size，并且释放删除的结点
		plist->tail = cur;
		plist->size--;
		DestoryNode(&Delete);
	}
	else {

		//拆除结点
		cur->_next = del_next;
		del_next->_prev = cur;

		plist->size--;
		DestoryNode(&Delete);
	}
}

//删除所有指定值的元素
void DLinkListRemoveAll(DLinkList* plist, DLinkType to_delete) {

	if (plist == NULL) {
		return;
	}
	int sz = plist->size;
	while (sz--) {

		//删除所有指定值的元素
		DLinkListRemove(plist, to_delete);

	}

}

//删除一个链表的所有元素
void DLinkListClear(DLinkList* plist) {

	if (plist == NULL) {
		return;
	}
	DLinkNode* cur = plist->head->_next;
	DLinkNode* to_free = plist->head->_next;

	plist->tail = plist->head;
	while (cur->_next != NULL) {

		cur = cur->_next;
		DestoryNode(&to_free);
		to_free = cur;

	}
	DestoryNode(&to_free);
	plist->head->_next = NULL;

}

test.c

#define _CRT_SECURE_NO_WARNINGS 1
#include"DLinkList.h"

#define TESTHEAD printf("//---------------%s-----------------\n",__FUNCTION__);

void TestPushBack() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");
}

void TestPopBack() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");

	DLinkListPopBack(plist);
	DLinkListPopBack(plist);
	DLinkListPopBack(plist);

	PrintChar(plist, "尾删三个元素");
}

void TestPushFront() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");

	DLinkListPushFront(plist, 'c');
	DLinkListPushFront(plist, 'b');
	DLinkListPushFront(plist, 'a');

	PrintChar(plist,"头插三个元素");
}

void TestPopFront() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");

	DLinkListPopFront(plist);
	DLinkListPopFront(plist);

	PrintChar(plist, "头删两个元素");
}

void TestFind() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkNode* pos_a = DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkNode* pos_f = DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");

	DLinkNode* cur1 = DLinkListFind(plist, 'a');
	if (pos_a->data == cur1->data) {
		printf("success!\n");
	}

}
void TestInsert() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkNode* pos_a = DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkNode* pos_f = DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");

	DLinkListInsert(plist,pos_a, 'u');
	PrintChar(plist, "在元素a之前插入元素u");

	DLinkListInsert(plist,pos_f, 'v');
	PrintChar(plist, "在元素f之前插入一个元素v");

}

void TestInsertAfter() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkNode* pos_a = DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkNode* pos_f = DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");

	DLinkListInsertAfter(plist,pos_a, 'u');
	PrintChar(plist, "在元素a之后插入元素u");

	DLinkListInsertAfter(plist,pos_f, 'v');
	PrintChar(plist, "在元素f之后插入元素v");
}

void TestErase() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkNode* pos_a = DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkNode* pos_f = DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");

	DLinkListErase(plist, pos_a);
	PrintChar(plist, "删除元素a");

	DLinkListErase(plist, pos_f);
	PrintChar(plist, "删除元素f");

}

void TestRemove() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");

	DLinkListRemove(plist, 'u');

	DLinkListRemove(plist, 'a');
	PrintChar(plist, "删除元素a");
	DLinkListRemove(plist, 'f');
	PrintChar(plist, "删除元素f");
	DLinkListRemove(plist, 'd');
	PrintChar(plist, "删除元素d");
}

void TestRemoveAll() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	PrintChar(plist, "尾插六个元素");

	DLinkListRemoveAll(plist, 'a');
	PrintChar(plist, "删除所有元素a");

}

void TestEmpty() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'a');
	PrintChar(plist, "尾插六个元素");

	int n = DLinkListEmpty(plist);
	printf("expect 0, actual: %d\n", n);

	DLinkListRemoveAll(plist, 'a');
	n = DLinkListEmpty(plist);
	printf("expect 1, actual:%d\n", n);
}

void TestClear() {
	DLinkList* plist = InitDLinkList();
	TESTHEAD;
	DLinkListPushBack(plist, 'a');
	DLinkListPushBack(plist, 'b');
	DLinkListPushBack(plist, 'c');
	DLinkListPushBack(plist, 'd');
	DLinkListPushBack(plist, 'e');
	DLinkListPushBack(plist, 'f');
	PrintChar(plist, "尾插六个元素");

	DLinkListClear(plist);
	PrintChar(plist, "删除链表里的所有元素");
}

int main() {
	TestPushBack();
	TestPopBack();
	TestPushFront();
	TestPopFront();
	TestFind();
	TestInsert();
	TestInsertAfter();
	TestErase();
	TestRemove();
	TestRemoveAll();
	TestEmpty();
	TestClear();
	system("pause");
	return 0;
}

应该还有不少bug，代码能力还有待加强，欢迎讨论