链表反转

#include <stdio.h>

struct node
{
 node *next;
 int data;
};

node *LInsert(node *head, int data);
node *LReverse(node *head);
void Lprint(node *head);

int main()
{
	node *head = NULL;
	for(int i=0;i<10;i++) //插入1-10到链表中
	{
		head = LInsert(head, i+1);
	}
	printf("Before Reverse:\n");
	Lprint(head);
	
	head = LReverse(head);
	printf("After Reverse:\n");
	Lprint(head);
	
	return 0;
}

node *LInsert(node *head, int data)
{
	node *p = NULL;
	node *q = NULL;
	if(head == NULL)
	{
		head = new node;
		head->data = data;
		head->next = NULL;
	}
	else
	{
		q = head;
		p = q->next;
		while(p != NULL)
		{
			q = p;
			p = p->next;
		}
		p = new node;
		p->data = data;
		p->next = NULL;
		q->next = p;
	}
	return head;
}

node *LReverse(node *head)
{
	node *pPre = NULL;
	node *pNow = NULL;
	node *pNext = NULL;

	if((head == NULL) || (head->next == NULL)) //no element or 1 element
	{
		return head;
	}
	else //2 or more elements
	{
		pPre = head;
		pNow = pPre->next;
		pNext = pNow->next;
		while(pNext != NULL)
		{
			pNow->next = pPre;
			pPre = pNow;
			pNow = pNext;
			pNext = pNext->next;
		}
		pNow->next = pPre; //important!!!
		head->next = NULL;
		return pNow;
	}
}

void Lprint(node *head)
{
	node *p = head;
	while(p != NULL)
	{
		printf("%d\n", p->data);
		p = p->next;
	}
}