c++写个循环单链表

以下是C++实现循环单链表的代码：

#include <iostream>
using namespace std;

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

class LinkedList {
private:
    Node* head;
public:
    LinkedList() {
        head = NULL;
    }

    void insert(int val) {
        Node* newNode = new Node;
        newNode->data = val;
        newNode->next = NULL;

        if (head == NULL) {
            head = newNode;
            head->next = head;
        }
        else {
            Node* temp = head;
            while (temp->next != head) {
                temp = temp->next;
            }
            temp->next = newNode;
            newNode->next = head;
        }
    }

    void display() {
        if (head == NULL) {
            cout << "List is empty" << endl;
        }
        else {
            Node* temp = head;
            do {
                cout << temp->data << " ";
                temp = temp->next;
            } while (temp != head);
            cout << endl;
        }
    }
};

int main() {
    LinkedList list;

    list.insert(1);
    list.insert(2);
    list.insert(3);
    list.insert(4);

    list.display();

    return 0;
}