《C和指针学习笔记》之双链表操作

主要参考代码来自：http://blog.csdn.net/l52188821/archive/2009/02/24/3933743.aspx

 

#include<stdio.h>#include<stdlib.h>typedef struct node{struct node *pre;struct node *next;int data;char *name;}Node; #define LEN (sizeof(Node))/*******************************************************************************************函数名称：Node* create_double_link(int n)*函数功能：创建升序排列的双链表*入口参数：链表节点个数*返 回 值：指向节点(结构体)的指针*******************************************************************************************/Node* create_double_link(int n){Node *current;Node *head;Node *new;int i;new = (Node*)malloc(LEN*n);if(NULL == new){return NULL;}for(i = 0; i < n; i++){new->data = (i+1)*2;/*如果是头结点，要赋值给head，用于返回*/if(0 == i){new->name = "head";new->pre = NULL;head = new;/*头结点不用current->next = new;*/current = new;new++;}/*如果是尾节点*/else if((n-1) == i){new->name = "tail";new->pre = current;/*开始写成current->next = NULL，导致没有尾节点;*/{current->next = new;new->next = NULL;}/*尾节点不用current = new;*//*尾节点不用new++;*/}/*中间节点，实际上相当于在双链表的尾部插入新节点*/else{new->name = "body";new->pre = current;current->next = new;current = new;new++;}}/*头结点的前驱是空*/head->pre = NULL;return head;}/*******************************************************************************************函数名称：int insert_double_link(Node **linkp, int data, char *name)*函数功能：创建往升序排列的双链表中插入新的节点*入口参数：linkp, 指向链表头节点的指针的指针; data, 新节点的数值字段; name, 新节点的名称字段*返 回 值：-1, 内存申请失败; 1, 插入成功*******************************************************************************************/int insert_double_link(Node **linkp, int data, char *name){Node *current;Node *new;while((current = *linkp) != NULL && current->data < data){linkp = ¤t->next;}new = (Node*)malloc(LEN);/*如果申请内存失败，返回-1*/if(new == NULL){return -1;}new->data = data;new->name = name;/*不是尾节点*/if(current != NULL){new->pre = current->pre;current->pre = new;}new->next = current;*linkp = new;return 1;}/*******************************************************************************************函数名称：int delete_double_link(Node**p, int data)*函数功能：删除升序排列的双链表中的节点*入口参数：p, 指向链表头节点的指针的指针; data, 所删除节点的数值字段; *返 回 值：-1, 内存申请失败; 1, 插入成功*******************************************************************************************/int delete_double_link(Node**p, int data){Node *q;q = *p;while(q->data != data )/*相当不解的是while((q->data != data) && (q != NULL))当data值不在链表中时就出错*/{q = q->next;if (q == NULL)break;}/*所要删除的值不在链表中，返回0*/if(q == NULL){return 0;}#if 1if(*p == q){*p = (*p)->next ;(*p)->pre = NULL;}else if(q->next == NULL){q->pre->next =NULL;//free(q);}else{q->pre->next = q->next;q->next->pre = q->pre ;}return 1;#endif}int main(){Node *p, *p2;p = create_double_link(3);insert_double_link(&p, 1, "body");p2 = p;while(p != NULL){printf("The node's name is %s, and data is %d/n", p->name, p->data);p = p->next;}delete_double_link(&p2, 1);while(p2 != NULL){printf("The node's name is %s, and data is %d/n", p2->name, p2->data);p2 = p2->next;}return 0;}