C和指针 十二章 双链表没有实现

这一章主要讲了链表；

单链表和双链表，由于某些原因，只实现了单链表；双链表等我看到后边数据结构再回来补上去

#include <stdio.h>#include <stdlib.h>//这段代码参考了c和指针以及深入浅出C语言程序设计链表一部分，但是插入元素的那段代码是深入浅出那里的，比较简单typedef struct NODE{    int value;    struct NODE *link;} Node;Node *head;//使用数组建立动态链表,先创建头节点，再创建第一个数据节点，并连接到头节点后面，如果再有新数据就再创建节点Node *creatlist( int *a, int n);void outputlist( Node *head);//链表输出void insertlist( Node *head, int x );//插入一个值void deletelist( Node *head, int new_value );int main(){    int a[10]= { 10, 20, 30, 40, 50 }, i;    printf("数组初值是 \n");    for( i = 0; i < 5; i++ )    {        printf( "%d\t", a[i]);    }    printf("\n");    head = creatlist( a, 5 );    printf( "使用数组元素创建的动态链表：\n");    outputlist( head );    int x;    x=25;    insertlist( head, x );    deletelist( head, x );    outputlist( head );    return 0;}Node *creatlist( int *a, int n){    Node *head, *p1, *p2;    int i;    head = (Node *) malloc( sizeof( Node ) );    if( head == NULL)    {        printf("没有分配足够内存");        exit(0);    }    p1 = head;    for( i = 0; i < n; i++ )    {        p2 = malloc( sizeof( Node ) );        if( p2 == NULL)        {            printf("没有分配足够内存");            exit(0);        }        p1->link = p2;        p2->value = a[i];        p1 = p2;    }    p1->link = NULL;    return head;}void outputlist( Node *head)//输出链表{    Node *p;    p = head->link;    printf("head->");    while( p != NULL )    {        printf("%d->", p->value);        p = p->link;    }    printf("NULL\n");}void insertlist( Node *head, int new_value ){    Node *current;    Node *precious;    Node *news;    precious = head;    current = head->link;    while(  current != NULL )    {        if( current->value < new_value )        {        precious = current;        current = current->link;        }       else        break;    }    news =(Node *) malloc( sizeof (Node) );    if (news == NULL)    {        printf("出错\n");        exit(0);    }    news->value = new_value;    news ->link = current;    precious->link = news;    outputlist( precious );}void deletelist( Node *head, int new_value ){    Node *current;    Node *precious;    precious = head;    int flag;    current = head->link;    while(  current != NULL )    {        if( current->value == new_value )        {        flag = 1;        break;        }     precious = current;     current = current->link;    }    if( flag == 1)    {            precious->link = current->link;    }    outputlist( precious );}