数据结构——循环队列的基本操作（C语言实现）

1、定义

#define QUEUE_DEFAULT_SIZE 8
typedef struct CycleSeqQueue
{
	ElemType *base;
	int       capacity;
	int       front;
	int       rear;
}CycleSeqQueue;

2、判空、判满

bool IsFull(CycleSeqQueue *pcq)
{
	assert(pcq != NULL);
	return ((pcq->rear + 1) % (pcq->capacity + 1)) == pcq->front;
}
bool IsEmpty(CycleSeqQueue *pcq)
{
	assert(pcq != NULL);
	return pcq->front == pcq->rear;
}

3、初始化

void CycleSeqQueueInit(CycleSeqQueue *pcq)
{
	assert(pcq != NULL);
	pcq->capacity = QUEUE_DEFAULT_SIZE;
	pcq->base = (ElemType*)malloc(sizeof(ElemType)* (pcq->capacity + 1));
	pcq->front = pcq->rear = 0;
}

4、入队、出队

void CycleSeqQueueEn(CycleSeqQueue *pcq, ElemType x)
{
	assert(pcq != NULL);
	if (IsFull(pcq))
	{
		printf("队列已满， %d 不能入队.\n", x);
		return;
	}
	pcq->base[pcq->rear] = x;
	pcq->rear = (pcq->rear + 1) % (pcq->capacity + 1);
}

void CycleSeqQueueDe(CycleSeqQueue *pcq)
{
	assert(pcq != NULL);
	if (IsEmpty(pcq))
	{
		printf("队列以空, 不能出队.\n");
		return;
	}
	pcq->front = (pcq->front + 1) % (pcq->capacity + 1);
}

5、取对头元素

ElemType CycleSeqQueueFront(CycleSeqQueue *pcq)
{
	assert(pcq != NULL);
	assert(!IsEmpty(pcq));
	return pcq->base[pcq->front];
}

6、求队列元素个数

int CycleSeqQueueSize(CycleSeqQueue *pcq)
{
	assert(pcq != NULL);
	int size = 0;
	for (int i = pcq->front; i != pcq->rear;)
	{
		size++;
		i = (i + 1) % (pcq->capacity + 1);
	}
	return size;
}

7、打印

void CycleSeqQueueShow(CycleSeqQueue *pcq)
{
	assert(pcq != NULL);
	for (int i = pcq->front; i != pcq->rear;)
	{
		printf("%d ", pcq->base[i]);
		i = (i + 1) % (pcq->capacity + 1);
	}
	printf("\n");
}

8、摧毁

void CycleSeqQueueDestroy(CycleSeqQueue *pcq)
{
	assert(pcq != NULL);
	free(pcq->base);
	pcq->base = NULL;
	pcq->capacity = pcq->front = pcq->rear = 0;
}

测试用例和运行结果