用c语言写一段代码 1. 实现单循环链表的初始化、求数据元素个数、插入、删除、取数据元素等操作； 2. 用插入法建立带头结点的单循环链表；

#include <stdio.h>
#include <stdlib.h>

// 定义单循环链表节点结构体
typedef struct Node {
    int data;
    struct Node* next;
} Node;

// 初始化单循环链表
Node* createList() {
    Node* head = (Node*)malloc(sizeof(Node));
    if (!head) {
        printf("Memory allocation failed.\n");
        return NULL;
    }
    head->data = 0; // 设置头结点的数据为0
    head->next = head; // 将头结点的next指向自身形成循环链表
    return head;
}

// 求链表元素个数
int getLength(Node* head) {
    int count = 1;
    Node* temp = head->next;
    while (temp != head) {
        ++count;
        temp = temp->next;
    }
    return count;
}

// 插入元素
void insert(int value, Node** head_ref) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    if (!newNode) {
        printf("Memory allocation failed.\n");
        return;
    }
    newNode->data = value;
    newNode->next = (*head_ref)->next;
    (*head_ref)->next = newNode;
    newNode->next->next = *head_ref; // 维持循环链表结构
}

// 删除元素
void deleteElement(Node** head_ref, int value) {
    if (*head_ref == NULL) {
        printf("List is empty.\n");
        return;
    }

    Node* temp = *head_ref, *prev = NULL;
    while (temp != NULL && temp->data != value) {
        prev = temp;
        temp = temp->next;
    }

    if (temp == NULL) {
        printf("Value not found in the list.\n");
        return;
    }

    if (prev == NULL) { // 如果待删除的是头结点
        *head_ref = temp->next;
        free(temp);
    } else {
        prev->next = temp->next;
        free(temp);
    }
}

// 取数据元素
int getData(Node* head) {
    if (head == NULL) {
        printf("List is empty.\n");
        return -1;
    }
    return head->data;
}

int main() {
    Node* head = createList();
    
    // 测试并展示功能
    printf("Initial list length: %d\n", getLength(head));

    insert(5, &head);
    printf("After inserting 5: ");
    printList(head); // 自定义函数用于打印链表

    deleteElement(&head, 5);
    printf("After deleting 5: ");
    printList(head);

    printf("Head node data: %d\n", getData(head));

    return 0;
}

// 打印链表辅助函数
void printList(Node* head) {
    Node* temp = head;
    while (temp != head->next) {
        printf("%d ", temp->data);
        temp = temp->next;
    }
    printf("%d\n", temp->data); // 输出最后一个元素
}