80 lines
1.5 KiB
C
80 lines
1.5 KiB
C
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//循环队列
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#include <stdio.h>
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#include <stdlib.h>
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#include "ring_queue.h"
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//#define RING_QUEUE_DEBUG
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//#ifdef RING_QUEUE_DEBUG
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//#define //rq_debug term_printf
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//#else
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//void rq_debug(const char *fmt, ...){};
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//#endif
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//初始化队列
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int InitRingQueue(RingQueue *q, RQ_ElementType *buff, int size)
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{
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q->elems = buff;
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q->size = size;
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q->front=q->rear=0;
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return RQ_OK;
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}
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//遍历队列,
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//消费者使用，故对生产者可能修改的rear先读取缓存
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int ShowRingQueue(RingQueue *q)
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{
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//int i;
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int rear = q->rear;
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if(q->front == rear)
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{
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//rq_debug("队列为空\n");
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return RQ_ERROR;
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}
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//rq_debug("队列中的元素为:\n");
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//for(i=((q->front)%q->size); i != rear; i=((i+1)%q->size))
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//rq_debug(" %c\n",q->elems[i]);
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//rq_debug("\n");
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//rq_debug("队首元素为%c\n",q->elems[q->front]);
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//rq_debug("队尾元素为%c\n",q->elems[rear - 1]);
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return RQ_OK;
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}
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//向队尾插入元素e
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int InRingQueue(RingQueue *q,RQ_ElementType e)
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{
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if(RingQueueFull(q))
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{
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//rq_debug("空间不足\n");
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return(RQ_OVERFLOW);
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}
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q->elems[q->rear] = e;
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q->rear = (q->rear+1) % q->size;
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//rq_debug("rear = %d\n",q->rear);
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return RQ_OK;
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}
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//从队首取回并删除元素
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int OutRingQueue(RingQueue *q, RQ_ElementType *e)
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{
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if(RingQueueEmpty(q))
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{
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//rq_debug("队列为空\n");
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return RQ_ERROR;
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}
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*e = q->elems[q->front];
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//rq_debug("被删除的队首元素为%c\n",q->elems[q->front]);
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q->front = (q->front+1) % q->size;
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return RQ_OK;
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}
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//队列中的元素个数
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int RingQueueLength(RingQueue *q)
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{
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return ((q->rear - q->front) + q->size) % q->size;
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}
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