关于双链表的相关操作

来源：互联网发布：航天飞机知乎编辑：程序博客网时间：2024/04/28 19:32
#include <stdio.h>#include <stdlib.h>#include <string.h>struct node {int data;struct node *next;struct node *prev;};struct node *create_node(int num){struct node *p = (struct node*)malloc(sizeof(struct node));if(p == NULL){printf("error");return NULL;}bzero(p,sizeof(struct node));p->data = num;p->prev = NULL;p->next = NULL;return p;}void insert_tail(struct node *head,struct node *new){struct node *p = head;while(p->next != NULL){p = p->next;}p->next = new;new->next = NULL;new->prev = p;}void insert_head(struct node *head,struct node *new){new->next = head->next;if(head->next != NULL){head->next->prev = new;}head->next = new;new->prev = head;//head->next->prev = new;}void insert_middle(struct node *head,struct node *new,int num){int flag = 0;struct node *p = head;struct node *temp = NULL;while(p->next != NULL){p = p->next;temp = (struct node*)malloc(sizeof(struct node));temp->data = new->data;if(p->data == num){if(p->next == NULL){p->next = new;new->prev = p;new->next = NULL;flag = 1;}else{temp->next = p->next;p->next->prev = temp;p->next = temp;temp->prev = p;p = p->next;free(temp);temp = NULL;flag = 1;}}}if(flag == 0){printf("NO find! insert error!\n");}}#if 1int  delete_node(struct node *head,int num){struct node *p = head;struct node *ptr = NULL;while(p->next != NULL){ptr = p;p = p->next;if(p->data == num){if(p->next == NULL){ptr->next = NULL;free(p);p = NULL;}else{ptr->next = p->next;p->next->prev = ptr;free(p);p = NULL;}return 0;}}}#endifstruct node *display(struct node *head){struct node *p = head;while(p->next != NULL){p = p->next;printf("%d\n",p->data);}return p;}void display_tail(struct node *p){while(p->prev != NULL){printf("%d\n",p->data);p = p->prev;}}int main(){struct node *head = create_node(0);int i = 0;struct node *ptr = (struct node*)malloc(sizeof(struct node));for(i = 0;i < 5;i++){struct node *new = (struct node *)malloc(sizeof(struct node));new->data = i+1;//insert_tail(head,new);insert_head(head,new);}struct node *new = (struct node*)malloc(sizeof(struct node));new->data = 3;insert_head(head,new);ptr = display(head);printf("前向遍历：\n");display_tail(ptr);printf("中间插入：\n");new = (struct node *)malloc(sizeof(struct node));new->data = 18;insert_middle(head,new,3);display(head);printf("删除结点:\n");delete_node(head,4);display(head);printf("再次前序遍历:\n");display_tail(ptr);return 0;}
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