#include "stdio.h"
#include "string.h"
#include "malloc.h"
#define NULL 0
#define LEN sizeof(struct stu)
struct stu
{
    int num;
    struct stu *next;
}*p1,*p2;
struct stu *creat()
{
    int temp;
    struct stu *head=NULL;
    printf("input temp:\n");
    scanf("%d",&temp);
    while(temp!=0)
    {
        p1=(struct stu *)malloc(LEN);
        if(head==NULL)
            head=p1;
        else
            p2->next=p1;
        p1->num=temp;
        p2=p1;
        printf("\ninput number:");
        scanf("%d",&temp);
    }
    p2->next=NULL;
    return(head);
}


void output(struct stu *head)
{
    for(p1=head;p1!=NULL;p1=p1->next)
    {
        
        printf("%4d",p1->num);
        p1=p1->next;
    }
}
struct stu *turnback(struct stu *head)
{
    struct stu *a,*newhead,*temp;
    p2=head;
    p1=head->next;
    head->next=NULL;
    while(p1!=NULL) //这个while循环是如何将链表逆顺序输出的？
    {
        temp=p1->next;//这个p1->next是指第一个结点还是第二个节点？
        p1->next=p2;
        p2=p1;
        p1=temp;
    }
    newhead=p2;
    return(newhead);
}



int main(int argc, char* argv[])
{
     struct stu *head;
    head=creat();

    printf("the original list:\n");
    output(head);
    head=turnback(head);
    printf("\nthe new list:\n");
    output(head);
    printf("\n");

    return 0;
}