数据结构－双链表

双链表（Double Linked List）

 

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|  lLink(左链指针)  |       data (数据)     |     rLink  (有链指针)       |

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   单链表中，搜索一个指定结点的后继结点非常方便，只要该结点的 link 域的内容不为空，就可以通过 link域找到结点的后继结点地址。但是要搜索一个指定的前驱结点十分不容易，必须从链头开始，沿 link 链顺序检测，直到某一个结点的后继结点为该指定结点，则此结点即为该节点的前驱结点。为了客服这一缺点，可以考虑双向链表。

 

下面给出了一些双向链表的操作程序，包括，insert, delete, search, output....

 

#include "string.h"#include "stdlib.h"#include "stdio.h"typedef struct Student{ char name[20]; struct Student *Llink,*Rlink;}Node;Node *CreateNode(int len){Node *head,*prior,*current;head=(Node*)malloc(sizeof(Node));if (head==NULL){ printf("fail to create head");return 0;}head->name[0]='/0'; // end of'/0'head->Llink=NULL;head->Rlink=NULL;prior=head;for(int i=0;i<len;++i){ current=(Node*)malloc(sizeof(Node));if (current==NULL){printf("fail to create head");return 0;}printf("请输入第 %d 个人的姓名：",i+1);scanf("%s",current->name);prior->Rlink=current;current->Llink=prior;prior=current;current->Rlink=NULL;}head->Llink=current;current->Rlink=head;return head;}void OutputDlink(Node *head){Node *p;p=head->Rlink;while (p!=head){printf("%s/n",p->name);p=p->Rlink;}}int lengthDlink(Node *head){int len=0;Node *cur=head->Rlink;while (cur!=head){cur=cur->Rlink;len++;}return len;}Node *SearchNode(Node *head,const char *name){Node *pNode=head->Rlink;while (pNode!=head){if (strcmp(pNode->name,name)==0){return pNode;}elsepNode=pNode->Rlink;}printf("没有找到该节点！");return 0;}void DeleteNode(Node *pNode){ Node *temp;if (pNode!=NULL) { temp=pNode;pNode=pNode->Rlink;temp->Llink->Rlink=pNode;pNode->Llink=temp->Llink;delete(temp); }}void InsertNode(Node *pNode,const char *name)//此函数是在输入节点的前面插入{ Node *newNode=new(Node); strcpy(newNode->name,name); newNode->Llink=pNode->Llink; newNode->Rlink=pNode; pNode->Llink->Rlink=newNode; pNode->Llink=newNode;}void InsertNodeAfter(Node *pNode,const char *name){Node *newNode=new(Node); strcpy(newNode->name,name); pNode->Rlink->Llink=newNode; newNode->Rlink=pNode->Rlink; newNode->Llink=pNode; pNode->Rlink=newNode;}void main(){Node *headNode=NULL;int count=0;printf("请输入双向链表的长度：");int length=0;scanf("%d",&length);headNode=CreateNode(length);OutputDlink(headNode); // count=lengthDlink(headNode);//printf("%d",count);printf("---------------");/*printf("请输入要删除的节点");char deName[20];Node *curNode=NULL;scanf("%s",deName);curNode=SearchNode(headNode,deName); DeleteNode(curNode);OutputDlink(headNode);*/printf("请输入要添加节点的前一个节点：");char inname[20];Node *inNode=NULL;scanf("%s",inname);inNode=SearchNode(headNode,inname);printf("请输入添加节点的姓名：");char insertName[20];scanf("%s",insertName);InsertNodeAfter(inNode,insertName);OutputDlink(headNode);}