期末考试必备----数据结构----顺序表之链表的模拟和相关操作（创建，头插，尾插，删除，定位，打印）

					/*链表的相关操作*/

#define ok 1
#define error 0
#define overflow -2

typedef int status;
typedef int elemtype;

typedef struct node
{
	elemtype data;
	struct node* next;
}Lnode, *Llist;

/*status*/void create01(Llist& L, int n)
{
	int i;
	L = (Llist)malloc(sizeof(Lnode));/**/
	//if (L == NULL)
	//	return error;

	L->next = NULL;

	Llist p, s;//p:追踪链尾，s:新建节点
	p = L;/**/

	printf("请输入你要创建的%d个元素的值(尾插，顺序创建)\n", n);
	for (i = 0; i < n; i++)
	{
		s = (Llist)malloc(sizeof(Lnode));

		//if (s == NULL)
		//	return error;

		scanf("%d", &s->data);
		p->next = s;

		//尾插
		p = p->next;
	}
	p->next = NULL;/**/

	//return ok;
}

void create02(Llist& L)
{
	L = (Llist)malloc(sizeof(Lnode));/*创建头节点*/
	L->next = NULL;

	//尾部插入节点
	printf("请输入你要创建的元素值，以0结尾(尾插，顺序创建)\n");
	int val;
	scanf("%d", &val);

	Llist s, p;
	p = L;

	while (val)
	{
		s = (Llist)malloc(sizeof(Lnode));
		s->data = val;

		//尾插
		p->next = s;
		p = p->next;
		scanf("%d", &val);
	}
	p->next = NULL;/**/
}


void create03(Llist& L)
{
	L = (Llist)malloc(sizeof(Lnode));/**/
	L->next = NULL;

	printf("请输入你要创建的元素值，以0结尾(头插，逆序创建)\n");
	int val;
	scanf("%d", &val);

	Llist s;

	while (val)
	{
		s = (Llist)malloc(sizeof(Lnode));
		s->data = val;

		//头插
		s->next = L->next;
		L->next = s;
		scanf("%d", &val);
	}
}

void print(Llist& L)
{
	Llist q;/*注意不是Lnode，因为要指向next指针*/
	q = L->next;
	printf("打印链表元素\n");
	while (q)
	{
		printf("%d ", q->data);
		q = q->next;
	}
	printf("\n");
}

int getnum(Llist L)
{
	Llist q;/*注意不是Lnode，因为要指向next指针*/
	int n = 0;
	q = L->next;
	while (q)
	{
		q = q->next;
		n++;
	}

	return n;
}

status myinsert(Llist& L, int i, int e)
{
	if (i < 1)
		return error;

	Llist q = L;
	int j = 0;
	while (q != NULL && j < i - 1)
	{
		j++;
		q = q->next;
	}

	if (q == NULL)
		return error;

	Llist s = (Llist/*注意：不要打星号*/)malloc(sizeof(Lnode));
	s->data = e;
	s->next = q->next;
	q->next = s;
	return ok;
}

status myerase(Llist& L, int i)
{
	if (i < 1)
		return error;

	int j = 0, e;
	Llist q = L;
	while (q != NULL && j < i - 1)
	{
		j++;
		q = q->next;
	}

	if (q == NULL)
		return error;
	e = q->next->data;

	Llist p = q->next;
	q->next = q->next->next;
	free(p);
	p = NULL;
	return e;
}

Llist locat(Llist& L, int i)
{
	if (i < 1)
		return NULL;

	int j = 0;
	Llist q = L;
	while (q != NULL && j < i/**/)
	{
		j++;
		q = q->next;
	}
	if (q == NULL)
		return NULL;

	return q;
}

int main()
{
	Llist L1;
	int n;

	//尾插---->正向输出----->都需要一个指针p去跟踪链表末尾
	//已知元素个数创建
	//printf("请输入你要创建的链表元素个数:\n");
	//scanf("%d", &n);
	//create01(L1, n);
	create02(L1);
	print(L1);
	printf("链表元素个数为:%d\n", getnum(L1));

	//Llist L2;
	头插---->逆序输出
	以0为结尾输入的创建
	//create03(L2);

	//print(L2);
	//printf("链表元素个数为:%d\n",getnum(L2));

	int i, e;

	//注意插入和删除数据都是要定位到该位置的前面一个

	//插入数据
	printf("请输入你要插入的位置和数据\n");
	scanf("%d%d", &i, &e);
	myinsert(L1, i, e);
	print(L1);

	//删除数据
	printf("请输入你要删除的位置\n");
	scanf("%d", &i);
	e = myerase(L1, i);
	if (e == 0)
		printf("删除位置非法，删除失败\n");
	else
	{
		printf("删除的数据为：%d，删除成功\n", e);
		print(L1);
	}

	//定位
	printf("请输入你要定位的元素位置\n");
	scanf("%d", &i);
	Llist q = locat(L1, i);
	if (q == NULL)
		printf("定位非法，定位失败\n");
	else
		printf("%p\n", q);
	return 0;
}