c++ 链表相关

#include 
#include 
#include 

#define ok 1
#define error 0

struct linklist
{
	int id;
	struct linklist *next;
};

int init_linklist(struct linklist **head);
int insert_linklist(struct linklist *head);
int traver_linklist(struct linklist *head);
int chang_linklist(struct linklist **head);


int main(int argc,char *argv[])
{
	int i=0;
	struct linklist *head;
	init_linklist(&head);
	while (i < 5)
	{
		insert_linklist(head);
		i++;
	}
	
	traver_linklist(head);

	chang_linklist(&head);

	traver_linklist(head);
	return ok;
}


int init_linklist(struct linklist **head)
{
	*head = (struct linklist *)malloc(sizeof(struct linklist));
	if (NULL == (*head))
	{
		printf("init error\n");
		return error;
	}

	memset(*head,0,sizeof(struct linklist));
	(*head)->next = NULL;

	return ok;
}

int insert_linklist(struct linklist *head)
{
	struct linklist *s;
	struct linklist *p = head->next;
	struct linklist *upper = head;
	s = (struct linklist *)malloc(sizeof(struct linklist));
	if (NULL == s)
	{
		printf("init error\n");
		return error;
	}
	memset(s,0,sizeof(struct linklist));
	printf("please input the num:\t");
	scanf("%d",&s->id);
	s->next = NULL;

	while ( p != NULL  && p->id id)
	{
		upper = p;
		p = p->next;
	}
	 s->next = p;
	 upper->next = s;
	return ok;	
}


int traver_linklist(struct linklist *head)
{
	struct linklist *p;
	p = head->next ;
	while ( p!= NULL)
	{
		printf("%d--",p->id);
		p = p->next;
	}
	printf("\n");

}


int chang_linklist(struct linklist **head) //实现单链表的就地逆转
{
	struct linklist *p = (*head)->next;
	struct linklist *q = NULL;
	struct linklist *r = NULL;

	while (p  != NULL)
	{
		q = p->next;
		p->next = r;
		r = p;
		p = q;
	}
	 
//	free(*head);
//	*head = NULL;


	
	(*head)->next = r;


}