C++ 实现简单的单向链表

为了练习一下对链表的理解，尝试手动造*，实现单向链表的右添加，左添加和删除的功能。

头文件

#pragma once
#include<iostream>
using namespace std;
struct Node//节点
{
	int value;
	Node* next;
	Node(int a = 0, Node* n = NULL) :value(a), next(n) {}
};
class List
{
private:
	Node* head = NULL;//头指针
	Node* tail = NULL;//尾指针，便于在尾部添加节点
	int size = 0;
public:
	int getSize() { return size; }//获取链表大小
	void print();//打印链表
	void append(int a);//右添加
	void appendleft(int a);//左添加
	void remove(int a);//删除节点
};

源文件

#include "List.h"

void List::append(int a)
{
	Node *p = new Node(a);
	if (head)
	{
		tail->next = p;
		tail = p;
	}
	else
	{
		head = p;
		tail = p;
	}
	size++;
}
void List::appendleft(int a)
{
	Node *p = new Node(a);
	if (head)
	{
		p->next = head;
		head = p;
	}
	else
	{
		head = p;
		tail = p;
	}
	size++;
}
void List::remove(int a)
{
	Node* p = head;
	bool flag = false;
	if (!head)
	{
		flag = false;
		cout << "链表已空，无需删除！" << endl;
	}
	else if (head->value == a && head != tail)
	{
		head = head->next;
		delete p;
		size--;
		flag = true;
		cout << "删除成功！" << endl;
	}
	else if (head->value == a && head == tail)
	{
		head = NULL, tail = NULL;
		delete p;
		size--;
		flag = true;
		cout << "删除成功！" << endl;
	}
	else
	{
		Node*q = head->next;
		while (q)
		{
			if (q->value == a && q != tail)
			{
				p->next = q->next;
				delete q;
				size--;
				flag = true;
				cout << "删除成功！" << endl;
				break;
			}
			else if (q->value == a && q == tail)
			{
				p->next = NULL;
				tail = p;
				delete q;
				size--;
				flag = true;
				cout << "删除成功！" << endl;
				break;
			}
			else
			{
				p = q;
				q = p->next;
			}
		}
		if (!flag)
			cout << "查无此值:" << a << endl;
	}
}
void List::print()
{
	if (!head)
		cout << "链表为空，无法输出！" << endl;
	else
	{
		cout << "链表为:" ;
		Node*p = head;
		while (p)
		{
			cout << p->value << " ";
			p = p->next;
		}
		cout << endl;
	}
}

主程序验证

int main()
{
	List list1;
	list1.append(3);
	list1.append(4);
	list1.appendleft(5);
	list1.appendleft(6);
	list1.append(2);
	cout << "----链表大小:" << list1.getSize() << endl;
	list1.print();
	list1.remove(5);
	cout << "----链表大小:" << list1.getSize() << endl;
	list1.print();
	list1.remove(7);
	cout << "----链表大小:" << list1.getSize() << endl;
	list1.print();
	list1.remove(6);
	cout << "----链表大小:" << list1.getSize() << endl;
	list1.print();
	list1.remove(4);
	cout << "----链表大小:" << list1.getSize() << endl;
	list1.print();
	list1.remove(3);
	cout << "----链表大小:" << list1.getSize() << endl;
	list1.print();
	list1.remove(2);
	cout << "----链表大小:" << list1.getSize() << endl;
	list1.print();
	system("pause");
	return 0;
}

验证结果