带表头节点的循环双向链表（头插，尾插，中间插，清除，前向显示，后向显示）

最新推荐文章于 2024-08-23 23:19:13 发布

原创最新推荐文章于 2024-08-23 23:19:13 发布 · 676 阅读

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CC 4.0 BY-SA版权

本文介绍了一个简单的双向链表实现，包括节点的创建、插入及反转等基本操作，并通过实例展示了如何构建和遍历双向链表。

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

struct dblnode
{
	int num;
	struct dblnode *prior,*next;
};

typedef struct dblnode Dblnode;
typedef struct dblnode* Dbllink;

int is_malloc_ok(Dbllink *newnode)
{
	if((*newnode) == NULL)
	{
		printf("malloc error!\n");
		exit(-1);
	}
	return 0;
}

int create_newnode(Dbllink *newnode)
{
	*newnode = (Dbllink)malloc(sizeof(Dblnode));
	is_malloc_ok(newnode);
	return 0;
}

int create_dbllink(Dbllink *head)
{
	create_newnode(head);
	(*head)->prior = (*head)->next = *head;
	return 0;
}

int insert_node_head(Dbllink *head,Dbllink *newnode)
{
	(*newnode)->next = (*head)->next;
	(*newnode)->prior = *head;
	(*head)->next->prior = *newnode;
	(*head)->next = *newnode;

	return 0;
}

int insert_node_tail(Dbllink *head,Dbllink *newnode)
{
	(*newnode)->prior = (*head)->prior;
	(*newnode)->next = *head;
	(*head)->prior->next = *newnode;
	(*head)->prior = *newnode;
	return 0;
}

int insert_node_mid(Dbllink *head,Dbllink *newnode,int num)
{
	Dbllink tmp = (*head)->next;
	if(tmp == *head)
	{
		printf("no such node!\n");
		return 0;
	}
	while(tmp->num != num && tmp != *head)
	{
		tmp = tmp->next;
	}
	if(tmp->num == num)
	{
		(*newnode)->prior = tmp;
		(*newnode)->next = tmp->next;
		tmp->next->prior = *newnode;
		tmp->next = *newnode;
	}
	else
	{
		printf("no such node!\n");
	}
}

int revers(Dbllink *head)
{
	Dbllink tmp = (*head)->next;
	while(tmp != *head)
	{
		tmp->prior->next = tmp->next;
		tmp->next->prior = tmp->prior;
		free(tmp);
		tmp = tmp->next;
	}
	printf("revers success!\n");
	return 0;
}

int display_forword_link(Dbllink *head)
{
	Dbllink tmp = (*head)->prior;

	if(tmp == *head)
	{
		printf("only have head_node");
		return 0;
	}

	while(tmp != *head)
	{
		printf("num = %d\n",tmp->num);
		tmp = tmp->prior;
	}
	return 0;
}

int display_afterword_link(Dbllink *head)
{
	Dbllink tmp = (*head)->next;
	if(tmp == *head)
	{
		printf("only have head_node!\n");
		return 0;
	}
	while(tmp != *head)
	{
		printf("num = %d\n",tmp->num);
		tmp = tmp->next;
	}
	return 0;
}

int main()
{
	Dbllink head = NULL;
	Dbllink newnode = NULL;
	int i;
	int num;

	create_dbllink(&head);

	for(i=0;i<10;i++)
	{
		create_newnode(&newnode);
		newnode->num = i;
		insert_node_head(&head,&newnode);
		//insert_node_tail(&head,&newnode);
	}

	printf("Enter a number!\n");
	scanf("%d",&num);

	create_newnode(&newnode);
	newnode->num = num;

	insert_node_mid(&head,&newnode,newnode->num);

	display_forword_link(&head);
	
	revers(&head);

	display_afterword_link(&head);

    return 0;
}