C++ 实现链表常用功能

首先头文件，定义了链表的常用函数：

typedef struct node
{
	int data;
	struct node* next;
} Node;

class LinkListUtil
{
public:
	LinkListUtil();
	~LinkListUtil();

	//create
	Node* createByArray(int arr[], int len);

	int getLenght(Node *head);

	void println(Node *head);

	Node* remove(Node *head, int num);

	//Insert element into the link list by the index.
	//if index is -1 then insert the num into the link list end.
	Node* insert(Node *head, int num, int index = -1);

	Node* sort(Node *head);

	Node* reserve(Node *head);

	Node* removeHead(Node *head);
};

然后是实现：

#include "stdafx.h"
#include "LinkListUtil.h"

LinkListUtil::LinkListUtil()
{
}

LinkListUtil::~LinkListUtil()
{
}

Node* LinkListUtil::createByArray(int arr[], int len)
{
	//Declare head node, previous node, new node.
	Node *head, *p, *n;

	//Init head node.
	head = new Node();

	p = head;

	for (int i = 0; i < len; i++)
	{
		n = new Node();
		n->data = arr[i];
		p->next = n;
		p = n;
	}
	head = head->next;
	//head->next = nullptr;	//?
	return head;
}

int LinkListUtil::getLenght(Node *node)
{
	int len = 0;
	Node *temp = node;
	while (temp != nullptr)
	{
		temp = temp->next;
		len++;
	}
	return len;
}

void LinkListUtil::println(Node *node)
{
	Node *temp = node;
	while (temp != nullptr)
	{
		printf("the node data is : %d\n", temp->data);
		temp = temp->next;
	}
}

Node* LinkListUtil::remove(Node *head, int num)
{
	Node *temp = head;
	Node *pre = nullptr;
	//find the node
	while (temp != nullptr)
	{
		if (temp->data != num)
		{
			pre = temp;
			temp = temp->next;
		}
		else
		{
			break;
		}
	}
	if (pre == nullptr)
	{
		head = head->next;
	}
	else {
		pre->next = temp->next;
	}
	delete temp;
	return head;
}

Node* LinkListUtil::insert(Node *head, int num, int index)
{
	int len = getLenght(head);
	if (index >= len)
	{
		printf("The index is greater than the length of link list!\n");
		return head;
	}
	Node *temp = head;
	Node *pre = nullptr;
	//if index is -1 then insert the num into the link list end.
	int tempIndex = 0;
	if (index <= -1)
		index = len;
	//find the insert point.
	while (temp != nullptr && index != tempIndex)
	{
		tempIndex++;
		pre = temp;
		temp = temp->next;
	}
	//insert the num.
	Node *nd;
	nd = new Node();
	nd->data = num;
	if (pre == nullptr)
	{
		nd->next = head;
		delete pre, temp;
		return nd;
	}
	else {
		nd->next = temp;
		pre->next = nd;
		return head;
	}
}

Node* LinkListUtil::sort(Node *head)
{
	//if only has one element or none elements
	if (head == nullptr || head->next == nullptr)
		return head;

	Node *p0, *p1;
	int temp = 0;
	p0 = head;
	//bubble sort
	while (p0 != nullptr && p0->next != nullptr)
	{
		p1 = p0->next;
		while (p1 != nullptr)
		{
			if (p0->data > p1->data)
			{
				temp = p0->data;
				p0->data = p1->data;
				p1->data = temp;
			}
			p1 = p1->next;
		}
		p0 = p0->next;
	}
	return head;
}

Node* LinkListUtil::reserve(Node *head)
{
	//if only has one element or none elements
	if (head == nullptr || head->next == nullptr)
		return head;

	Node *p0, *p1, *p2;
	p0 = head;
	p1 = p0->next;
	while (p1 != nullptr)
	{
		p2 = p1->next;
		p1->next = p0;
		p0 = p1;
		p1 = p2;
	}
	head->next = nullptr;
	return p0;
}

Node* LinkListUtil::removeHead(Node *head)
{
	//if only has one element or none elements
	if (head == nullptr || head->next == nullptr)
		return head;
	Node *p0;
	p0 = head->next;
	head->next = p0->next;
	head = p0;
	return head;
}

最后是main测试：

// Win32Project2.cpp
//

#include "stdafx.h"
#include <iostream>
#include <string>
#include <assert.h>

#include "LinkListUtil.h"

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
	//////////////////////////////////////////////////////////////////////////

	int arr[5] {3, 1, 9, 4, 6};

	auto linkList = new LinkListUtil();
	auto head = linkList->createByArray(arr, 5);
	//Get linkList size;
	auto len = linkList->getLenght(head);
	printf("LinkList's length:%d\n", len);

	printf("Print LinkList:\n");
	linkList->println(head);

	printf("Remove element 1 and print LinkList:\n");
	head = linkList->remove(head, 1);
	linkList->println(head);

	printf("Insert element 5 into the index 1 and print LinkList:\n");
	head = linkList->insert(head, 5, 1);
	linkList->println(head);

	printf("Insert element 2 into the end and print LinkList:\n");
	head = linkList->insert(head, 2);
	linkList->println(head);

	printf("Bubble sort:\n");
	head = linkList->sort(head);
	linkList->println(head);

	printf("reserve:\n");
	head = linkList->reserve(head);
	linkList->println(head);

	printf("remove head:\n");
	head = linkList->removeHead(head);
	linkList->println(head);
	//clear
	delete linkList;
	//////////////////////////////////////////////////////////////////////////
	system("pause");
	return 0;
}