c/c++链表学习

链表学习持续更新

这边设置链表的节点，里面包含两个信息分别是数据域（可以用自己写的类或者基本数据结构，为了简便这边直接使用基本数据类型）和指向下一节点的指针。

struct SeqList
{
int data;
SeqList *next;
};

1.首先是创建链表

SeqList *creatlist(int n)
{
	SeqList* head = new SeqList;
	head->data = 100;
	SeqList *p = head;
	for (int i = 0; i <= n;i++)
	{
		SeqList *q = new SeqList;
		q->data = i;
		q->next = NULL;
		p->next = q;
		p = q;
	}	

	return head;
}

2.修改链表内容

void change_point(SeqList *head, int n, int number)
{
	SeqList *p = head;
	while (n)
	{
		p = p->next;
		n--;
	}
	p->data = number;
}

3.删除节点

void delete_point(SeqList *head, int n)
{
	
	SeqList *p = head;
	SeqList *tmp = new SeqList;
	while (n>1)
	{
		p = p->next;
		n--;
	}
	tmp = p->next;
	p->next = tmp->next;
	delete tmp;
}

4.插入节点

void insert_point(SeqList *head, int n, int val)
{
	SeqList *listnode = new SeqList;
	listnode->data = val;
	SeqList*p = head;
	while (n>0)
	{
		p = p->next;
		n--;
	}
	listnode->next = p->next;
	p->next = listnode;
}

5.计算链表长度

int listlength(SeqList * head)
{
	int count = 0;
	SeqList*p = head;
	while (p->next!=NULL)
	{
		p = p->next;
		count++;
	}
	return count;
}

6.打印链表

void print_list(SeqList*head)
{
	if (head->next==NULL)
	{
		return;
	}
	SeqList *p = head->next;
	while (p->next!=NULL)
	{
		cout << p->data << endl;
		p = p->next;
	}
}

7.清空&销毁链表

//清空链表
void clearlist(SeqList*head)
{
	if (head==NULL)
	{
		return;
	}
	SeqList *p = head->next;
	while (p != NULL)
	{
		SeqList *q = p->next;
		delete p;
		p = NULL;
		p = q;
	}
	head->next = NULL;
}
//销毁链表
void destroylist(SeqList*head)
{
	clearlist(head);
	delete head;
	head = NULL;
}

8.反转链表

SeqList* reverse(SeqList* head){
	SeqList* pPrev = nullptr;
	SeqList* p = head;
	SeqList* pReverseHead = nullptr;
	while (p != nullptr){
		SeqList* pNext = p->next;
		if (pNext == nullptr){
			pReverseHead = p;
		}
		p->next = pPrev;
		pPrev = p;
		p = pNext;
	}
	return pReverseHead;
}

9.获取倒数第N个结点

使用快慢指针，先让快指针 q q q走到第N个结点位置，然后让快慢指针一起走，直至快指针的下一个指向NULL

//获得倒数第N个指针（使用快慢指针的方法）
SeqList*getrelistnode(SeqList*head, int n)
{
	SeqList *p = head;
	SeqList*q = head;
	for (int i = 0; i < n;i++)
	{
		q = q->next;
	}
	while (q->next!=NULL)
	{
		p = p->next;
		q = q->next;
	}
	return p;
}

每个函数执行在main()函数中实现

void main()
{
	SeqList * head = new SeqList;
	head=creatlist(10);//创建链表
	listlength(head);//计算链表长度
	//change_point(head, 3, 20);//修改元素
//	delete_point(head, 2);//删除链表节点
	//insert_point(head, 4, 40);//插入链表节点
	head=reverse(head);
	print_list(head);
	clearlist(head);//清空
	destroylist(head);//销毁
	return;
}