使用C++实现链表的基本操作

#include <stdio.h>
#include <iostream>

using namespace std;
typedef class List
{
public:
	int data;
	List *next;
}node;

/*
	单链表的创建
	无参数，输入任意非0数字创建链表，输入0结束创建
	返回head头指针
	存在BUG：第一次输入0时，内存发生错误（已解决，无法打印出head->data的值）
*/
node *create()
{	
	node *head;						//头指针
	node *p;						//指示指针，用于记录存入位置
	node *s;						//链表节点
	int x;
	int n = 0;						//表示链表长度
	int cycle = 1;
	head = (node*)malloc(sizeof(node));
	p = head;
	while(cycle)
	{
		cout << "\n请您输入数据:" << endl;
		cin >> x;
		if(0 != x)							//输入0结束
		{
			s = (node*)malloc(sizeof(node));
			s->data = x;
			++n;
			cout << "创建节点" << n<< "成功，您输入的数据为：" << s->data;
			p->next = s;
			p = s;
		}
		else
			cycle = 0;
	}
	if(0 != n)
	{
		
		head = head->next;
		p->next = NULL;
		cout << "链表创建完毕，第一个元素为" << head->data << endl;
	}
	else
	{
		head->next = NULL;
		head = NULL;
		cout << "链表为空" << endl;
	}
	
	return head;
}  

/*
	单链表测长
	传入参数为链表头指针
	返回链表长度（int）
*/
int length(node *head)
{
	int n = 0;						//链表长度
	node *p;
	p = head;
	while(NULL != p)
	{
		p = p->next;
		++n;
	}
	return n;
}

/*
	单链表打印
	传入参数为链表头指针
	无返回值
*/
const void print(node *head)
{
	node *p;
	int n;
	p = head;
	n = length(head);
	cout << "链表中共有" << n << "个元素:" <<endl;
	if(NULL != head)
	{
		while(NULL != p)
		{
			cout << p->data << " ";
			p = p->next; 
		}
	}
	cout <<endl;
}

/*
	单链表的删除
	传入参数1：单链表头指针；参数2：删除节点的数据
	返回head头指针
	存在BUG：无法删除头结点(已解决，需要有头指针接收删除后的头指针)
*/
node *del(node *head, int num)
{
	node *p1;
	node *p2;
	p1 = head;
	while(num!=p1->data && NULL!=p1->next)
	{
			p2 = p1;
			p1 = p1->next;
	}
	if(num == p1->data)
	{
		if(p1 == head)
		{
			head = p1->next;
			free(p1);
		}
		else
			p2->next = p1->next;
	}
	else
		cout << "元素" << num << "无法在链表中找到" << endl;
	return head;
}

/*
	单链表的插入（头插法）
	传入参数1：单链表头指针；参数2：插入节点的数据
	返回head头指针
*/
node *insert(node *head ,int num)
{
	node *p0;
	node *p1;
	node *p2;
	p1 = head;
	p0 = (node *)malloc(sizeof(node));
	p0->data = num;
	while((p0->data)>(p1->data) && NULL!=p1->next)
	{
		p2 = p1;
		p1 = p1->next;
	}
	if(p0->data <= p1->data)
	{
		if(head == p1)
		{
			p0->next = p1;
			head = p0;
		}
		else
		{
			p2->next = p0;
			p0->next = p1;
		}
	}
	else
	{
		p1->next = p0;
		p0->next = NULL;
	}
	return head;
}

/*
	单链表的排序
	传入参数为链表头指针
	返回值为排序后的链表头指针
*/
node *sort(node *head)
{
	node *p;
	int n;
	int temp;
	n = length(head);
	if(NULL == head || NULL == head->next)
		return head;
	p = head;
	for(int j = 1;j != n;j++)
	{
		p = head;
		for(int i = 0;i != n-j; i++)
		{
			if((p->data)>(p->next->data))
			{
				temp = p->data;
				p->data = p->next->data;
				p->next->data = temp;
			}
			p = p->next;
		}
	}
	return head;
}
/*
	单链表的逆序
	传入参数为链表头指针
	返回值为排序后的链表头指针
*/
node *reverse(node *head)
{
	node *p1;
	node *p2;
	node *p3;
	if(NULL == head || NULL == head->next)
		return head;
	p1 = head;
	p2 = p1->next;
	while(NULL != p2)
	{
		p3 = p2->next;
		p2->next = p1;
		p1 = p2;
		p2 = p3;
	}
	head->next = NULL;
	head = p1;
	return head;
}

void main(void)
{
	node *head;
	int length;
	int n;
	head = create();
	length = ::length(head);
	cout << "链表长度为：" << length << endl; 
	print(head);
	cout << "请输入要删除的数字" << endl;
	cin >> n;
	head = del(head,n);
	print(head);
	cout << "请输入要插入的数字" << endl;
	cin >> n;
	head = insert(head,n);
	print(head);
	sort(head);
	cout << "排序后的链表为：" << endl;
	print(head);
	head = reverse(head);
	cout << "倒序后的链表为：" << endl;
	print(head);
}