c语言-单链表（二）

//1.判断链表是否为空
bool isempty_list(PNODE pHead) {
	return pHead->pNext == NULL;
}

//2.链表长度
int length_list(PNODE pHead) {
	PNODE pFirst = pHead->pNext;//获取头结点
	int num = 0;
	while (pFirst != NULL)
	{
		num++;
		pFirst = pFirst->pNext;
	}
	return num;
}

//指索引位置插入节点
bool insert_list(PNODE pHead, int pos, int data) {
	PNODE p = pHead;//头结点
	int i = 0;
	while (p != NULL&&i <= pos)
	{
		p = p->pNext;
		i++;
	}
	//pos 是索引位置，循环i不能>pos+1
	if (p == NULL || i > (pos + 1))
	{
		return false;
	}
	PNODE pNew = (PNODE)malloc(sizeof(PNODE));
	if (NULL == pNew)
	{
		printf("内存分配失败");
		exit(-1);
	}
	pNew->data = data;
	pNew->pNext = p->pNext;

	int pVal = p->data;
	p->pNext = pNew;

	return true;
}

bool delete_list(PNODE pHead, int pos) {
	PNODE p = pHead->pNext;
	int i = 0;
	//这样循环为了获取pos 前面一个节点
	while (NULL != p&&i < pos - 1)
	{
		p = p->pNext;
		i++;
	}
	if (NULL == p || i > pos - 1)
	{
		return false;
	}

	PNODE q = p->pNext;
	p->pNext = p->pNext->pNext;

	free(q);
	q = NULL;
	return true;
}

//排序算法
void sort_list(PNODE pHead) {
	int len = length_list(pHead);
	PNODE p, q;
	int i, j, temp;
	for (i = 0, p = pHead->pNext; i < len - 1; i++, p = p->pNext)
	{
		for (j = i + 1, q = p->pNext; j < len; j++, q = q->pNext)
		{
			if (p->data > q->data)
			{
				temp = p->data;
				p->data = q->data;
				q->data = temp;
			}
		}
	}
	return;
}

void main(void) {

	PNODE pHead = create_list();
	if (isempty_list(pHead)) {
		printf("链表为空\n");
	}
	else {
		printf("链表不为空\n");
	}

	bool is_insert=insert_list(pHead, 2, 100);
	if (is_insert)
	{
		printf("链表在索引2出插入100 成功\n");
		show_list(pHead);
	}
	else {
		printf("链表在索引2出插入100 失败\n");
	}

	printf("删除节点索引：1\n");

	bool is_del=delete_list(pHead, 1);
	if (is_del)
	{
		printf("删除节点索引：1 成功\n");
		show_list(pHead);
	}
	else {
		printf("删除节点索引：1 失败\n");
	}
}