C语言 NOTE28

数据结构链表

数据存储在内存上可以不连续，可以将零散的内存联系起来，数据增删处理简单。

typedef struct DATALIST
{
	int data;
	PDataList next;
}DataList, *PDataList;

数据的插入方法：

• 尾插法

bool trail_data_list(int num, PDataList head)
{
	//判断是否为空链表
	if(NULL == head)
	{
		printf("add data error\n");
		return false;
	}
	//找出最后一个节点
	PDataList p = head;
	while(NULL != p->next)
	{
		p = p->next;
	}
	//插入节点
	PDataList tem = calloc(1, sizeof(DataList));
	tem->data = num;
	tem->next = NULL;
	p->next = tem;
	return true;	
}

• 头插法

bool head_data_list(int num, PDataList head)
{
	//判断头结点是否为空
	if(NULL == head)
	{
		printf("addr error\n");
		return false;
	}
	//插入节点
	PDataList p = calloc(1, sizeof(DataList));
	p->data = num;
	p->next = head->next;
	head->next = p;
	return true;
}

• 排序插法
  

bool sort_data_list(int num, PDataList head)
{
	//判断头结点是否为空
	if(NULL == head)
	{
		printf("addr error\n");
		return false;
	}
	

	
	//插入节点
	PDataList tem = calloc(1, sizeof(DataList));
	tem->data = num;
	//比链表中间结点小
	PDataList p = head->next;
	PDataList pos = p;
	while(p != NULL)
	{
		if(num < p->data)
		{
			tem->next= p;
			pos->next = tem;
			return true;
		}
		pos = p;
		p = p->next;
	}
	//num为最大值时：
	pos->next = tem;
	tem->next = NULL;
	
}

//删除节点：
bool delete_data_list(int num, PDataList head)
{
	if(NULL == head)
	{
		printf("addr error\n");
		return false;
	}
	PDataList pos = head->next;
	PDataList p = pos->next;
	while(NULL != p)
	{
		if(num == p->data)
		{
			pos->next = p->next;
			p->next = NULL;
			free(p);
			return true;
		}
		pos = p;
		p = pos->next;
	}
	printf("data not exist\n");
	return false;
}