链表

#include <iostream>
struct STU
{
	char name[32];
	int id;
};

#define DATA STU*
struct NODE
{
	DATA data;
	NODE* next;
};

class LinkList
{
public:

	NODE* head;//表头
	int len;//长度

	void Create()
	{
		head = (NODE*)malloc(sizeof(NODE));
		head->next = 0;	
		len = 0;
	}
	bool Insert(int pos, DATA data)
	{
		if (pos < 0 || pos > len)
			return false;
		NODE* n = (NODE*)malloc(sizeof(NODE));
		n->data = data;

		NODE* p = head;
		for (int i = 0;i < pos; ++i)
			p = p->next;
		n->next = p->next;
		p->next = n;
		len++;
		return true;
	}
	bool Erase(int pos)
	{
		if (pos < 0 || pos > len-1)
			return false;
		NODE* p = head;
		for (int i = 0;i < pos; ++i)
			p = p->next;
		//p  p->next  p->next->next
		NODE* nn = p->next->next;
		free(p->next);
		p->next = nn;
		len--;
		return true;
	}
	int Len()
	{
		return len;
	}
	DATA* Get(int pos)
	{
		if (pos < 0 || pos > len-1)
			return 0;
		NODE* p = head->next;
		for (int i = 0;i < pos; ++i)
			p = p->next;
		return &p->data;
	}
	void Clear()
	{
		NODE* p = head->next;
		while (p)
		{
			NODE* n = p->next;
			free(p);
			p = n;
		}
		head->next = 0;
		len = 0;
	}
	void Destroy()
	{
		Clear();
		free(head);
	}
};


void main()
{
	LinkList s;
	s.Create();

	STU* stu = (STU*)malloc(sizeof(STU));
	strcpy(stu->name, "abc");
	stu->id = 1;

	s.Insert(0, stu);

	stu = (STU*)malloc(sizeof(STU));
	strcpy(stu->name, "DEF");
	stu->id = 2;	
	s.Insert(1, stu);

	for (int i = 0;i < s.Len(); ++i)
	{
		//数据如果是STU   返回的是STU* q;    *q  
		//数据如果是STU*   返回的是STU** q;   *q
		STU** q = s.Get(i);
		std::cout<< (*q)->name <<", " <<(*q)->id <<"\n";
	}

	//因为存的数据是开了堆的，所以在表销毁之前，应该
	//把数据开的堆内存释放
	for (int i = 0;i < s.Len(); ++i)
	{
		STU* q = *s.Get(i);
		free(q);
	}

	s.Destroy();//销毁
}