使用c语言完成双向循环链表，并实现可查找功能

好的，以下是使用 C 语言完成双向循环链表并实现可查找功能的代码：

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

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

Node* createNode(int data) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    newNode->prev = NULL;
    newNode->next = NULL;
    return newNode;
}

void insertAtEnd(Node** head, int data) {
    Node* newNode = createNode(data);
    if (*head == NULL) {
        *head = newNode;
        (*head)->prev = *head;
        (*head)->next = *head;
        return;
    }
    Node* lastNode = (*head)->prev;
    lastNode->next = newNode;
    newNode->prev = lastNode;
    newNode->next = *head;
    (*head)->prev = newNode;
}

Node* search(Node* head, int data) {
    if (head == NULL) {
        return NULL;
    }
    Node* curr = head;
    do {
        if (curr->data == data) {
            return curr;
        }
        curr = curr->next;
    } while (curr != head);
    return NULL;
}

void printList(Node* head) {
    if (head == NULL) {
        printf("List is empty.\n");
        return;
    }
    Node* curr = head;
    do {
        printf("%d ", curr->data);
        curr = curr->next;
    } while (curr != head);
    printf("\n");
}

int main() {
    Node* head = NULL;
    insertAtEnd(&head, 1);
    insertAtEnd(&head, 2);
    insertAtEnd(&head, 3);
    insertAtEnd(&head, 4);
    insertAtEnd(&head, 5);
    printList(head);
    Node* node = search(head, 3);
    if (node != NULL) {
        printf("Found node with data %d.\n", node->data);
    } else {
        printf("Node not found.\n");
    }
    return 0;
}

希望这个代码能够帮助你完成你的任务！