链表逆序

#include<stdio.h>
#include<stdlib.h>

typedef struct NODE
{
    int data;
    struct NODE *next;    
}Node;

Node* reverse(Node *head)
{
    Node *p1, *p2, *p3;

    if(head == NULL || head->next == NULL)
    {
        return head;
    }
    
    p1 = head;
    p2 = p1->next;

    
    while(p2)
    {
        p3 = p2->next;
        p2->next = p1;
        p1 = p2;
        p2 = p3;
    }

    head->next = NULL;
    head = p1;

    return head;
}

Node* create()
{
    Node *p, *head, *s;
    int num;
    int i, x;    

    printf("please input the node number:");

    scanf("%d", &num);
    if(num <= 0)
    {
        printf("error! The input number is wrong!!!\n");
        return NULL;
    }

    head = (Node*)malloc(sizeof(Node));
    p = head;

    for(i = 0; i < num; i++)
    {
        scanf("%d", &x);
        s = (Node*)malloc(sizeof(Node));
        s->data = x;
        p->next = s;
        p = s;
        
    }

    head = head->next;
    p->next = NULL;

    return head;
    
}

void main()
{
    Node *head, *p;
    head = create();
    p = reverse(head);

    while(p)
    {
        printf("%d ", p->data);
        p = p ->next;
    }

    printf("\n");
    
}