c语言 双向链表的简单操作-创建插入删除

Posted 2022-01-28 duanqibo

数据结构-双向链表的创建、插入和删除

双向链表是数据结构中重要的结构，也是线性结构中常用的数据结构，双向指针，方便用户从首结点开始沿指针链向后依次遍历每一个结点，结点的前驱和后继查找方便。

#include <stdio.h>

#include <stdlib.h>

//双向链表结点的定义

typedef struct dbnode

int data;

struct dbnode *prio, *next;

DbNode, linkdblist;

 

//创建双向链表

DbNode *creatlist(void)

linkdblist *p, *q, *head;

q = p = (linkdblist *)malloc(sizeof(linkdblist));

p->next = NULL;

head = q;

p = (linkdblist *)malloc(sizeof(linkdblist));

scanf("%d", &p->data);

while (p->data != -1)

q->next = p;

p->prio = q;

q = p;

p = (linkdblist *)malloc(sizeof(linkdblist));

scanf("%d", &p->data);

q->next = NULL;

return head;

 

//输出双向链表

void print(linkdblist *head)

linkdblist *p;

p = head->next;

if (p == NULL)

printf("空链表！\n");

while (p != NULL)

printf("%d  ", p->data);

p = p->next;

 

//向双向链表中的第i个位置插入一个结点x

void insertdblist(linkdblist *head, int x, int i)

linkdblist *p, *q = head;

if (i == 1)

q = head;

else

q = q->next;

int c = 1;

while ((c<i - 1) && (q != NULL))

q = q->next;

c++;

if (q != NULL && q->next != NULL)

p = (linkdblist *)malloc(sizeof(linkdblist));

p->data = x;

p->prio = q;

p->next = q->next;

q->next = p;

q->next->prio = p;

else

printf("找不到插入的位置！");

 

//删除双向链表中指定位置上的一个结点

void deletelinkdblist(linkdblist *head, int i)

linkdblist *p, *q = head;

if (i == 1)

q = head;

else

q = q->next;

int c = 1;

while (c < i - 1 && q != NULL)

q = q->next;

c++;

if (q != NULL && q->next != NULL)

p = q->next;

p->prio = q;

p->prio->next = p->next;

p->next->prio = p->prio;

free(p);

else if (q->next == NULL)

p = q;

p->prio->next = NULL;

free(p);

else

printf("没有找到待删除的结点");

//双向链表的主函数

void main()

linkdblist *head;

head = creatlist();

print(head);

 

printf("\n\n====向双向链表的某位置插入一个值====\n");

int num, i;

printf("输入插入的位置：");

scanf("%d", &i);

printf("\n输入插入的值：");

scanf("%d", &num);

insertdblist(head, num, i);

print(head);

printf("\n");

 

printf("\n\n====删除双向链表的某位置上的一个值====\n");

int j;

printf("输入删除的位置：");

scanf("%d", &j);

deletelinkdblist(head, j);

print(head);

system("pause");

printf("\n");