用C语言写一个循环链表

好的，我会为您提供C语言的循环链表代码示例。

首先，我们需要定义一个链表节点的结构体，如下所示：

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

其中，`data` 用来存储节点的数据，`next` 则指向下一个节点。

接下来，我们需要定义循环链表，并实现以下操作：

1. 初始化链表

void initList(Node **head) {
    *head = NULL;
}

2. 在链表末尾添加节点

void append(Node **head, int data) {
    Node *newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    
    if (*head == NULL) {
        newNode->next = newNode;
        *head = newNode;
    } else {
        newNode->next = (*head)->next;
        (*head)->next = newNode;
        *head = newNode;
    }
}

3. 删除指定位置的节点

void delete(Node **head, int position) {
    if (*head == NULL) {
        return;
    }

    Node *current = *head;
    Node *prev = NULL;
    int i = 0;

    while (i != position) {
        prev = current;
        current = current->next;
        i++;

        if (current == *head) {
            return; // 到达链表末尾，没有找到指定位置的节点
        }
    }

    if (current == *head) {
        *head = prev;
    }

    prev->next = current->next;
    free(current);
}

4. 打印链表中每个节点的数据

void printList(Node *head) {
    if (head == NULL) {
        return;
    }

    Node *current = head->next;

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

使用这些操作，我们可以轻松地创建、修改和打印循环链表。完整的示例代码如下：

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

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

void initList(Node **head) {
    *head = NULL;
}

void append(Node **head, int data) {
    Node *newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    
    if (*head == NULL) {
        newNode->next = newNode;
        *head = newNode;
    } else {
        newNode->next = (*head)->next;
        (*head)->next = newNode;
        *head = newNode;
    }
}

void delete(Node **head, int position) {
    if (*head == NULL) {
        return;
    }

    Node *current = *head;
    Node *prev = NULL;
    int i = 0;

    while (i != position) {
        prev = current;
        current = current->next;
        i++;

        if (current == *head) {
            return;
        }
    }

    if (current == *head) {
        *head = prev;
    }

    prev->next = current->next;
    free(current);
}

void printList(Node *head) {
    if (head == NULL) {
        return;
    }

    Node *current = head->next;

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

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

    append(&head, 1);
    append(&head, 2);
    append(&head, 3);
    append(&head, 4);

    printList(head);

    delete(&head, 2);

    printList(head);

    return 0;
}