////  main.c//  LineList////  Created by Rubert on 16/9/11.//  Copyright © 2016年 Study. All rights reserved.//#include <stdio.h>//定义链表数据结构struct node{    int num;    struct node *next;    struct node *prior;};//函数声明struct node *create();void print();void linkedList();void headInsertLinkedList();void tailInsertLinkedList();void findLinkedList();void insertLinkedList();void deleteLinkedList();void circleInsertLinkedList();void doubleInsertLinkedList();int main(int argc, const char * argv[]) {    // insert code here...    //headInsertLinkedList();    //tailInsertLinkedList();    //findLinkedList();    //insertLinkedList();    //deleteLinkedList();    //circleInsertLinkedList();    doubleInsertLinkedList();    return 0;}/* * 头插入法创建链表 */void headInsertLinkedList() {    struct node *head = NULL;    struct node *p1;    for(int i = 1; i < 10; i ++) {        p1 = (struct node*)malloc(sizeof(struct node));        p1 -> num = i;        p1 -> next = head;        head = p1;    }    print(head);}/* * 尾插入法创建链表 */void tailInsertLinkedList() {    struct node *head = NULL;    struct node *p1,*p2;    p1 = p2 = (struct node*)malloc(sizeof(struct node));    for(int i = 1; i < 10; i ++) {        if(head == NULL) {            head = p1;        } else {            p2 -> next = p1;        }        p2 = p1;        p1 = (struct node*)malloc(sizeof(struct node));        p1->num = i;    }    print(head);}/** * 创建循环链表 */void circleInsertLinkedList() {    struct node *head = NULL;    struct node *p1,*p2;    p1 = p2 = (struct node*)malloc(sizeof(struct node));    for(int i = 1; i < 10; i ++) {        if(head == NULL) {            head = p1;        } else {                        if(i == 9) {                p1->next = head;            }            p2 -> next = p1;        }        p2 = p1;        p1 = (struct node*)malloc(sizeof(struct node));        p1->num = i;            }    print(head);}/** * 创建双向链表 */void doubleInsertLinkedList() {    struct node *head = NULL;    struct node *p1,*p2;    p1 = p2 = (struct node*)malloc(sizeof(struct node));    for(int i = 1; i < 10; i ++) {        if(head == NULL) {            head = p1;        } else {            /*if(i == 9) {                p1->next = head;            }*/            p2 -> next = p1;            p1 -> prior = p2;        }        p2 = p1;        p1 = (struct node*)malloc(sizeof(struct node));        p1->num = i;            }    print(head);}/* * 链表查找 */void findLinkedList() {        struct node *head = NULL;    struct node *p1;    for(int i = 1; i < 10; i ++) {        p1 = (struct node*)malloc(sizeof(struct node));        p1 -> num = i;        p1 -> next = head;        head = p1;    }        struct node *p;    p = head -> next;    int j = 1;    int i = 5;    while(p !=NULL && j < i)    {        p = p->next;        ++j;    }    printf("%6d %d %d\n",p->num, p, p->next);/*输出链表节点的值*/}/* * 链表中插入 */void insertLinkedList() {        struct node *head = NULL;    struct node *p1;    for(int i = 1; i < 10; i ++) {        p1 = (struct node*)malloc(sizeof(struct node));        p1 -> num = i;        p1 -> next = head;        head = p1;    }        struct node *p,*m;    p = head;    int j = 0;    int i = 5;    while(p !=NULL && j < i-1)    {        p = p->next;        ++j;    }        if(p == NULL) {        printf("error");    } else {        m = (struct node*)malloc(sizeof(struct node));        m->num = j;        m->next = p -> next;        p->next = m;    }        print(head);    }/* * 链表中删除 */void deleteLinkedList() {        struct node *head = NULL;    struct node *p1;    for(int i = 1; i < 10; i ++) {        p1 = (struct node*)malloc(sizeof(struct node));        p1 -> num = i;        p1 -> next = head;        head = p1;    }        struct node *p,*m;    p = head;    int j = 0;    int i = 5;    while(p !=NULL && j < i-2)    {        p = p->next;        ++j;    }        if(p == NULL) {        printf("error");    } else {        //m = (struct node*)malloc(sizeof(struct node));        //m->num = j;        //m->next = p -> next;        p->next = p->next->next;            }        print(head);    }/* * sample 1 */void linkedList(){    struct node *head;    head = NULL;//创建一个空表    head = create(head); /* 创建单链表 */    print(head);/* 打印单链表 */    }struct node *create(struct node *head) //返回的是与节点相同类型的指针{    struct node *p1,*p2;    int i = 1;    //利用malloc() 函数向系统申请分配一个节点    p1 = p2 = (struct node*)malloc(sizeof(struct node));//新节点    printf("请输入值，值小于等于0结束，值存放地址为：p1_ADDR= %d\n",p1);    scanf("%d",&p1->num);/*输入节点的值*/    p1->next=NULL;/*将新节点的指针置为空*/    while(p1->num > 0)/*输入节点的数值大于0*/    {        //④将新节点的指针成员赋值为空。若是空表，将新节点连接到表头；若是非空表，将新节点接到表尾;        if(head == NULL)            head = p1;/*空表，接入表头*/        else            p2->next = p1;/*非空表，接到表尾*/        p2 = p1;                p1 = (struct node*)malloc(sizeof(struct node));/*下一个新节点*/        i = i+1;        printf("请输入值，值小于等于0结束，值存放地址为：p%d_ADDR= %d\n",i,p2);        scanf("%d",&p1->num);/*输入节点的值*/        //⑤判断一下是否有后续节点要接入链表，若有转到3 )，否则结束;    }    //==============原来程序更正部分：（多谢@daling_datou提醒）================================    //free(p1);  //申请到的没录入，所以释放掉    p1 = NULL;   //使指向空    p2->next = NULL; //到表尾了，指向空    printf("链表输入结束（END）\n");    //==============================================    return head;}void print(struct node *head)/*出以head为头的链表各节点的值*/{    struct node *temp;    temp = head;/*取得链表的头指针*/        printf("\n\n\n链表存入的值为：\n");    while(temp != NULL)/*只要是非空表*/    {        printf("%6d %d %d %d\n",temp->num, temp, temp->next, temp->prior);/*输出链表节点的值*/        temp = temp->next;/*跟踪链表增长*/    }    printf("链表打印结束!!");}