设计循环单链表。循环单链表的操作，包括初始化，求元素个数，插入、删除元素、取元素，再设计一个测试主函数验证所设计循环单链表的正确性用c语言

以下是设计循环单链表的代码：

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

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

typedef struct List {
    Node* head;
    int size;
} List;

void initList(List* list) {
    list->head = NULL;
    list->size = 0;
}

int getSize(List* list) {
    return list->size;
}

void insert(List* list, int data) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    newNode->next = NULL;

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

    list->size++;
}

void delete(List* list, int data) {
    if (list->head == NULL) {
        return;
    }

    Node* current = list->head;
    Node* prev = NULL;

    while (current->data != data) {
        if (current->next == list->head) {
            return;
        }
        prev = current;
        current = current->next;
    }

    if (current == list->head && current->next == list->head) {
        list->head = NULL;
    } else if (current == list->head) {
        Node* last = list->head;
        while (last->next != list->head) {
            last = last->next;
        }
        list->head = current->next;
        last->next = list->head;
    } else if (current->next == list->head) {
        prev->next = list->head;
    } else {
        prev->next = current->next;
    }

    free(current);
    list->size--;
}

int get(List* list, int index) {
    if (index < 0 || index >= list->size) {
        return -1;
    }

    Node* current = list->head;
    for (int i = 0; i < index; i++) {
        current = current->next;
    }

    return current->data;
}

void printList(List* list) {
    if (list->head == NULL) {
        printf("List is empty\n");
        return;
    }

    Node* current = list->head;
    do {
        printf("%d ", current->data);
        current = current->next;
    } while (current != list->head);
    printf("\n");
}

int main() {
    List list;
    initList(&list);

    insert(&list, 1);
    insert(&list, 2);
    insert(&list, 3);
    insert(&list, 4);
    insert(&list, 5);

    printf("List size: %d\n", getSize(&list));
    printList(&list);

    delete(&list, 3);
    printf("List size: %d\n", getSize(&list));
    printList(&list);

    printf("Element at index 2: %d\n", get(&list, 2));

    return 0;
}

以上代码实现了循环单链表的初始化、求元素个数、插入、删除元素、取元素等操作，并且包含了一个测试主函数，可以验证所设计循环单链表的正确性。