数据结构一循环链表

#include <iostream>
using namespace std;

// 定义链表节点结构
struct Node {
    int data;
    Node* next;
};

// 初始化循环链表
void initList(Node* &head) {
    head = nullptr;
}

// 判断链表是否为空
bool isEmpty(Node* head) {
    return head == nullptr;
}

// 在链表尾部插入节点
void insertAtEnd(Node* &head, int data) {
    Node* newNode = new Node;
    newNode->data = data;

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

// 在链表头部插入节点
void insertAtFront(Node* &head, int data) {
    Node* newNode = new Node;
    newNode->data = data;

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

// 删除链表中的节点
void deleteNode(Node* &head, int data) {
    if (isEmpty(head)) {
        cout << "链表为空，无法删除节点" << endl;
        return;
    }

    Node* temp = head;
    Node* prev = nullptr;

    // 找到要删除的节点
    do {
        if (temp->data == data) {
            break;
        }
        prev = temp;
        temp = temp->next;
    } while (temp != head);

    // 如果找到了要删除的节点
    if (temp->data == data) {
        if (temp == head && temp->next == head) {
            // 链表中只有一个节点
            head = nullptr;
        } else if (temp == head) {
            // 删除头节点
            Node* last = head;
            while (last->next != head) {
                last = last->next;
            }
            head = head->next;
            last->next = head;
        } else {
            // 删除中间节点或尾节点
            prev->next = temp->next;
        }
        delete temp;
        cout << "节点 " << data << " 已删除" << endl;
    } else {
        cout << "未找到节点 " << data << endl;
    }
}

// 打印链表
void printList(Node* head) {
    if (isEmpty(head)) {
        cout << "链表为空" << endl;
        return;
    }

    Node* temp = head;
    do {
        cout << temp->data << " ";
        temp = temp->next;
    } while (temp != head);
    cout << endl;
}

int main() {
    Node* head;
    initList(head);

    insertAtEnd(head, 10);
    insertAtEnd(head, 20);
    insertAtEnd(head, 30);

    cout << "链表内容：" << endl;
    printList(head);

    insertAtFront(head, 5);
    cout << "链表内容：" << endl;
    printList(head);

    deleteNode(head, 20);
    cout << "链表内容：" << endl;
    printList(head);

    return 0;
}