假设以带头结点的循环链表表示队列,并且只设一个指针指向队尾元素结点，试编写相应的置空队、判队空、入队和出队算法’、‘

好的，我可以回答这个问题。以下是相应的代码：

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

struct Node {
    int data;
    struct Node* next;
};
 
struct Queue {
    struct Node *rear;
};
 
//创建空队列
void createQueue(struct Queue *q) {
    q->rear = NULL;
}
 
//判断队列是否为空
int isQueueEmpty(struct Queue *q) {
    return (q->rear == NULL);
}
 
//入队列
void enqueue(struct Queue *q, int data) {
    struct Node *temp = (struct Node*)malloc(sizeof(struct Node));
    temp->data = data;
    if (q->rear == NULL) {
        q->rear = temp;
        q->rear->next = q->rear;
    } else {
        temp->next = q->rear->next;
        q->rear->next = temp;
        q->rear = temp;
    }
}
 
//出队列
int dequeue(struct Queue *q) {
    if (isQueueEmpty(q)) {
        printf("队列为空！");
        return 0;
    }
    int data;
    if (q->rear->next == q->rear) {
        data = q->rear->data;
        free(q->rear);
        q->rear = NULL;
    } else {
        struct Node *temp = q->rear->next;
        data = temp->data;
        q->rear->next = q->rear->next->next;
        free(temp);
    }
    return data;
}

int main() {
    struct Queue q;
    createQueue(&q);
    if (isQueueEmpty(&q)) {
        printf("队列为空！\n");
    }
    enqueue(&q, 1);
    enqueue(&q, 2);
    enqueue(&q, 3);
    printf("队列出队的顺序是：%d %d %d\n", dequeue(&q), dequeue(&q), dequeue(&q));
    return 0;
}

希望能回答您的问题！下一个问题是？