[牛人杂谈] 循环队列的用法

typedef struct {

    int buffer[SIZE];

    int head;

    int tail;

    int count;

} CircularBuffer;



void push(CircularBuffer *cb, int data) {

    if (cb->count < SIZE) {

        cb->buffer[cb->head] = data;

        cb->head = (cb->head + 1) % SIZE;

        cb->count++;

    }

}



int pop(CircularBuffer *cb) {

    if (cb->count > 0) {

        int data = cb->buffer[cb->tail];

        cb->tail = (cb->tail + 1) % SIZE;

        cb->count--;

        return data;

    }

    return -1; // Buffer is empty

}

#include <stdio.h>

#include <stdlib.h>



#define MAX_SIZE 10



// 定义循环队列结构体

typedef struct {

    int *array;   // 存储队列元素的数组

    int front;    // 队头指针，指向队首元素

    int rear;     // 队尾指针，指向队尾元素的下一个位置

    int capacity; // 队列的最大容量

} CircularQueue;



// 初始化循环队列

CircularQueue* createQueue() {

    CircularQueue* queue = (CircularQueue*)malloc(sizeof(CircularQueue));

    queue->array = (int*)malloc(MAX_SIZE * sizeof(int));

    queue->front = 0;

    queue->rear = 0;

    queue->capacity = MAX_SIZE;

    return queue;

}



// 入队操作

void enqueue(CircularQueue* queue, int value) {

    // 检查队列是否已满

    if ((queue->rear + 1) % queue->capacity == queue->front) {

        printf("Queue is full. Enqueue operation failed.\n");

        return;

    }

    queue->array[queue->rear] = value;

    queue->rear = (queue->rear + 1) % queue->capacity;

}



// 出队操作

int dequeue(CircularQueue* queue) {

    // 检查队列是否为空

    if (queue->front == queue->rear) {

        printf("Queue is empty. Dequeue operation failed.\n");

        return -1; // 返回一个特殊值表示出错

    }

    int value = queue->array[queue->front];

    queue->front = (queue->front + 1) % queue->capacity;

    return value;

}



// 打印队列元素

void printQueue(CircularQueue* queue) {

    printf("Queue: ");

    int i = queue->front;

    while (i != queue->rear) {

        printf("%d ", queue->array[i]);

        i = (i + 1) % queue->capacity;

    }

    printf("\n");

}



int main() {

    CircularQueue* queue = createQueue();



    enqueue(queue, 10);

    enqueue(queue, 20);

    enqueue(queue, 30);

    printQueue(queue);



    int dequeued = dequeue(queue);

    printf("Dequeued element: %d\n", dequeued);

    printQueue(queue);



    free(queue->array);

    free(queue);

    return 0;

}