C语言数据结构——双向链表

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

typedef int ElemType;

typedef struct DNode{
	ElemType data;
	struct DNode *prior;
	struct DNode *next;
}DNode;

DNode* initList()
{
	DNode *head = (DNode*)malloc(sizeof(DNode));
	head->data = 0;
	head->prior = NULL;
	head->next = NULL;
	return head;
}
//初始化双向链表

DNode* getTail(DNode *L)
{
	DNode *p = L;
	while(p->next != NULL)
	{
		p = p->next;
	}
	return p;
}
//获取尾结点

int insertTail(DNode *tail,ElemType e)
{
	DNode *p = (DNode*)malloc(sizeof(DNode));
	p->data = e;
	p->next = NULL;
	p->prior = tail;
	tail->next = p;
	return 1;
}
//尾插法

int insertHead(DNode *L,ElemType e)
{
	DNode *p = (DNode*)malloc(sizeof(DNode));
	p->data = e;
	p->prior = L;
	p->next = L->next;
	if(L->next != NULL)
	{
		L->next->prior = p;
	}
	L->next = p;
	return 1;
}
//头插法

int insertNode(DNode *L,int pos,ElemType e)
{
	DNode *p = L;
	int i = 0;
	while(i < pos - 1)
	{
		p = p->next;
		i++;
		if(p == NULL)
		{
			return 0;
		}
	}
	DNode *q = (DNode*)malloc(sizeof(DNode));
	q->data = e;
	q->next = p->next;
	q->prior = p;
	if(p->next != NULL)
	{
		p->next->prior = q;
	}
	p->next = q;
	return 1;
}
//指定位置插入数据

int deleteNode(DNode *L,int pos)
{
	DNode *p = L;
	int i = 0;
	while(i < pos - 1)
	{
		p = p->next;
		i++;
		if(p == NULL)
		{
			return 0;
		}
	}
	DNode *q = p->next;
	if(q == NULL)
	{
		return 0;
	}
	p->next = q->next;
	if(q->next != NULL)
	{
		q->next->prior = p;
	}
	free(q);
	return 1;
}
//指定位置删除数据

void listNode(DNode *L)
{
	DNode *p = L->next;
	while(p != NULL)
	{
		printf("%d ",p->data);
		p = p->next;
	}
	printf("\n");
}
//遍历

void freeNode(DNode *L)
{
	DNode *p = L->next;
	while(p != NULL)
	{
		DNode *q = p->next;
		free(p);
		p = q;
	}
	L->next = NULL;
}
//释放双向链表

int main()
{
	DNode *list = initList();
	DNode *tail = getTail(list);
	insertHead(list,10);
	insertHead(list,20);
	insertTail(tail,30);
	tail = getTail(list);
	insertNode(list,2,15);
	listNode(list);
	deleteNode(list,3);
	listNode(list);
	freeNode(list);
	free(list);
	return 0;
}