双向链表的基本操作

来源：互联网发布：mac部分变成英文编辑：程序博客网时间：2024/05/21 03:26
#include <stdio.h>#include <stdlib.h>typedef struct List{     struct List *next,*prev;     int item;}List,*link;link init();    //链表的初始化link headinsert(); //每次在链表的头部添加新结点link orderinsert();  //创建一个顺序的链表link delete(link ,int);  //在链表中找到元素并删除void show(link );int main(){    List *p,*q,*L;    printf("头插入法创建双向链表： \n");    p = headinsert();    show(p->next);    printf("创建非降序双向链表： \n");    q = orderinsert();    show(q->next);    printf("删除指定元素： \n");    L = delete(q->next,20);    show(L);    return 0;}link init(){    List *st = malloc(sizeof(*st));    st->next = NULL;    st->prev = NULL;    return st;}link headinsert(){    int x;    List *st;    st = init();    while(scanf("%d",&x) != EOF)    {        st->item = x;        List *p = malloc(sizeof(*p));        st->prev = p;        p->next = st;        p->prev = NULL;        st = p;    }    return st;}link orderinsert(){    int x;    List *head,*st;    st = init();    head = st;    while(scanf("%d",&x) != EOF)  //顺序输入数据    {        List *q = malloc(sizeof(*q));        q->item = x;        st->next = q;        q->prev = st;        q->next = NULL;        st = st->next;    }    return head;}link delete(link st,int a){    List *p,*t;    int i = 0;    p = st;    while(st->next != NULL)    {        if(st->item == a)        {            st->prev->next = st->next;            st->next->prev = st->prev;            t = st->next;            free(st);            st = t;            i++;            break;        }        else          st = st->next;    }    if(!i)        printf("链表中没有此元素：%d！",a);    return p;}void show(link st){    int N = 0;    while(st->next != NULL)    {        printf("%5d",st->item);        st = st->next;        N++;    }    printf("\n");    printf("链表中元素个数为%d\n",N);}
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