c语言实现双链表

概述

双链表在单链表的基础上，稍加改动，主要添加一个前驱节点，大体和单链表相似。

代码

结构体、头文件等

#include<stdio.h>
#include<assert.h>
#include<stdlib.h>
#define true 1
#define false 0
#define bool char
//链表数据类型
typedef int ElementType;
//双链表
typedef struct DNode {
	ElementType data;
	struct DNode* next;
	struct DNode* prior;
} DNode;
bool intDNode(DNode** head);
bool insertNextDNode(DNode* p, DNode* s);
bool deleteDNode(DNode* p);
bool deleteNextDNode(DNode* p);
bool queryStartToEnd(DNode* head);
bool queryEndToStart(DNode* tail);

初始化

bool intDNode(DNode** head) {
	*head = (DNode*)malloc(sizeof(DNode));
	if (*head == NULL) {
		return false;
	}
	(*head)->data = 0;
	(*head)->next = NULL;
	(*head)->prior = NULL;
	return true;
}

再p节点之后，插入s节点

bool insertNextDNode(DNode* p, DNode* s) {
	if (p->next) {
		p->next->prior = s;
	}
	s->next = p->next;
	s->prior = p;
	p->next = s;
	return true;
}

删除指定节点p

bool deleteDNode(DNode* p) {
	if (p->next) {
		p->next->prior = p->prior;
	}
	p->prior->next = p->next;
	free(p);
	return true;
}

删除当前节点的后继节点

bool deleteNextDNode(DNode* p) {
	DNode* q = p->next;
	if (p == NULL) {
		return false;
	}
	p->next = q->next;
	if (q->next == NULL) {
		return false;
	}
	q->next->prior = p;
	free(q);
	return true;
}

从前往后遍历

bool queryStartToEnd(DNode* head) {
	DNode* p = head;
	while (p)
	{
		printf("%d", p->data);
		p = p->next;
	}
	return true;
}

从后往前遍历

bool queryEndToStart(DNode* tail) {
	DNode* p = tail;
	while (p)
	{
		printf("%d", p->data);
		p = p->prior;
	}
	return true;
}