初学c语言链表，就不幸的卡在了这里
注释处为错误；
#include<stdio.h>
#include<stdlib.h>
#include<alloc.h>            // Cannot open include file: 'alloc.h': No such file or directory
struct node{
    int data;
    struct node *next;
}

int main()
{
    struct node *head,*p1,*p2;
    head =(struct node *)malloc(sizeof(struct node));
    p1 =(struct node *)malloc(sizeof(struct node));
    p2 =(struct node *)malloc(sizeof(struct node));
    head->data=1000;head->next=p1;
    p1->data=1001;p1->next=p2;
    p2->data=1002;p2->next=NULL;
    while (head!=NULL){
        printf("%d\n",head->data);
        p1=head;
        head=head->next;
        free(p1);
    }
    return 0;
}

太感谢了