c++实现带头结点的单链表的基本操作

本文参考代码：https://blog.csdn.net/qq_35143440/article/details/78896638

目录结构：

LinkList.h

struct ListNode {
	int val;//数据域
	ListNode* next;//指针域
};
class LinkList
{
public:
	LinkList();
	~LinkList();
	void CreateLinkList(int n);
	void TravelLinkList();
	int getLength();
	bool isEmpty();
	bool findData(int data);//查找节点，如果能够找到，返回true；否则返回false;
	void InsertElemAtEnd(int data);            //在尾部插入指定的元素
	void InsertElemAtIndex(int data, int n);    //在指定位置插入指定元素
	void InsertElemAtHead(int data);           //在头部插入指定元素
	void DeleteElemAtEnd();       //在尾部删除元素
	void DeleteAll();             //删除所有数据
	void DeleteElemAtPoint(int data);     //删除指定的数据
	void DeleteElemAtHead();//在头部删除节点
private:
	ListNode *head;
};

LinkList.cpp

#include "stdafx.h"
#include "LinkList.h"
#include <iostream>
using namespace std;
LinkList::LinkList()
{
	head = new ListNode;
	head->val = 0;
	head->next = NULL;
}


LinkList::~LinkList()
{
	delete head;
}

void LinkList::CreateLinkList(int n) {
	if (n < 0) {
		cout << "节点个数错误，请重新输入" << endl;
		exit(EXIT_FAILURE);
	}
	else {
		ListNode* p = head;
		ListNode* nextNode;
		for (int i = 0; i < n;i++) {
			nextNode = new ListNode;
			cout << "请输入新节点的值域" << endl;
			cin >> nextNode->val;
			nextNode->next = NULL;
			p->next = nextNode;
			p = p->next;
		}
	}
}

void LinkList::TravelLinkList() {
	if (head == NULL || head->next == NULL) {
		cout << "链表为空" << endl;
	}
	else {
		ListNode* p = head;
		while (p ->next!= NULL) {
			p = p->next;
			cout << p->val << endl;
		}
	}
}
int LinkList::getLength() {//头结点不计入总长度
	int length = 0;
	ListNode* p = head->next;
	while (p != NULL) {
		length++;
		p = p->next;
	}
	return length;
}
bool LinkList::isEmpty() {
	if (head == NULL) {
		return true;
	}
	else {
		return false;
	}
}
bool LinkList::findData(int data)//查找节点，如果能够找到，返回true；否则返回false;
{
	if (head == NULL || head->next == NULL) { return false; }
	else {
		ListNode* p = head->next;
		while (p != NULL) {
			if (p->val == data) { return true; }
			else { p = p->next; }
		}
		return false;
	}
}
void LinkList::InsertElemAtEnd(int data)//在尾部插入指定的元素
{
	//准备好新的节点
	ListNode* newNode;
	newNode = new ListNode;
	newNode->val = data;
	newNode->next = NULL;
	//在链表尾部插入节点
	if (head == NULL) { head = newNode; }
	else {
		ListNode* p = head;
		while (p->next != NULL) {
			p = p->next;
		}
		p->next = newNode;
	}

}
void LinkList::InsertElemAtIndex(int data, int n)//在指定位置插入指定元素,插入的元素在head之后。
{
	int length = this->getLength();
	if (n > length||n<1) { cout << "输入的位置不存在" << endl; }
	else {
		ListNode* p = head;
		ListNode* q = head->next;
		ListNode* newNode=new ListNode;
		newNode->val = data;
		newNode->next = NULL;
		int i = 0;
		for (; i != n; i++) {
			p = p->next;
			q = q->next;
		}
		p->next = newNode;
		newNode->next = q;
	}
}
void LinkList::InsertElemAtHead(int data)//在头部插入指定元素
{
	ListNode* newNode = new ListNode;
	newNode->val = data;
	newNode->next = NULL;
	if (head == NULL) { head = newNode; }
	else { 
		newNode->next = head->next;
		head->next = newNode;
	}
}
void LinkList::DeleteElemAtEnd()//在尾部删除元素
{
	if (head == NULL) { cout << "链表为空，无须删除" << endl;; }
	else {
		ListNode* p = head;
		ListNode* q = head->next;
		while (q->next != NULL) {
			p = p->next;
			q = q->next;
		}
		p->next = NULL;
		delete q;
	}

}
void LinkList::DeleteAll()//删除所有数据
{
	if (head == NULL) { ; }
	else {
		ListNode* p = head->next;
		//ListNode* p_temp = new ListNode;
		while (p != NULL) {
			/*p_temp = p;
			p = p->next;
			head->next = p;
			p_temp->next = NULL;
			delete p_temp;*/
			head->next = p->next;
			delete p;
			p = head->next;
		}
	}
	

}
void LinkList::DeleteElemAtPoint(int data)//删除指定的数据
{
	//也就是说要考虑data 是否存在的两种情况。
	if (findData(data)) {
		//如果能够找到该数据
		ListNode* p = head;
		ListNode* q = head->next;
		while (q->val != data) {
			p = p->next;
			q = q->next;
		}
		//此时q的值为data,接下来删除q节点。
		p->next = q->next;
		q->next = NULL;
		delete q;
	}
}
void LinkList::DeleteElemAtHead()//在头部删除节点
{
	if (head == NULL) { ; }
	else {
		ListNode* p = head;
		ListNode* q = head->next;
		p->next = q->next;
		delete q;
	}
}

source.cpp

#include<vector>
using namespace std;

int main()
{	
	LinkList lst;
	int i;
	int pos;
	int data;
	cout << "1.创建单链表   2.遍历单链表   3.获取单链表的长度   4.判断单链表是否为空   5.获取节点\n";
	cout << "6.在尾部插入指定元素   7.在指定位置插入指定元素   8.在头部插入指定元素\n";
	cout << "9.在尾部删除元素   10.删除所有元素   11.删除指定元素   12.在头部删除元素   0.退出" << endl;
	do {
		cout << "请输入指令" << endl;
		cin >> i;
		switch (i)
		{
		case 1:
			cout << "请输入表单的长度" << endl;
			int length;
			cin >> length;
			lst.CreateLinkList(length);
			continue;
		case 2:
			lst.TravelLinkList();
			continue;
		case 3:
			cout << "该链表的长度为" << lst.getLength()<<endl;
			continue;
		case 4:
			cout << "该链表是否为空 " << lst.isEmpty() << endl;
			continue;
		case 5:
			cout << "输入待寻找的数值：" << endl;
			cin >> data;
			cout << "是否找到了该数 " << lst.findData(data)<<endl;
			continue;
		case 6:
			cout << "请输入在结尾插入的数据" << endl;
			cin >> data;
			lst.InsertElemAtEnd(data);
			continue;
		case 7:
			cout << "请输入插入数据的位置" << endl;
			cin >> pos;
			cout << "请输入插入的数据" << endl;
			cin >> data;
			lst.InsertElemAtIndex(data, pos);
			continue;
		case 8:
			cout << "请输入插入的数据" << endl;
			cin >> data;
			lst.InsertElemAtHead(data);
			continue;
		case 9:
			lst.DeleteElemAtEnd();
			continue;
		case 10:
			lst.DeleteAll();
			continue;
		case 11:
			cout << "请输入要删除的数据" << endl;
			cin >> pos;
			lst.DeleteElemAtPoint(pos);
			continue;
		case 12:
			lst.DeleteElemAtHead();
			continue;
		default:
			break;
		}
	} while (i != 0);
		return 0;
}