循环队列的实现

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/*队列是一种先进先出的线性表,具有线性表的特性:分为链式队列与顺序队列顺序队列:用一段地址连续的存储单元存储数据元素，定义两个游标:指向队头的游标(front)、指向队尾的游标(rear),如果front == rear队列为空,如果(rear + 1) % MAXSIZE == front队列满(此为循环队列),如普通队列rear==MAXSIZE队列满 */#ifndef QUEUE_H#define QUEUE_H#define MAXSIZE 20  //队列的最大长度typedef int ElemType; //队列的数据类型typedef struct{ElemType data[MAXSIZE]; //队列int front; //队头的游标int rear;  //队尾的游标}Queue;void InitQueue(Queue *q); //初始化队列void EnQueue(Queue *q,ElemType e); //元素e进队void DeQueue(Queue *q,ElemType *e); //队头的元素出队bool IsEmpty(Queue *q); //判断队列是否为空int GetQueueLength(Queue *q); //返回队列的长度void Clear(Queue *q); //清空队列void Print(Queue *q); //打印队列#endif //QUEUE_H

#include "Queue.h"#include <stdio.h>void InitQueue(Queue *q) //初始化队列{q->front = q->rear = 0;}void EnQueue(Queue *q,ElemType e) //让元素e进队{if((q->rear + 1) % MAXSIZE == q->front) //队列已满return;q->data[q->rear] = e; //元素e进队q->rear = (q->rear + 1) % MAXSIZE; //游标rear上前进一位,如果已达最后,就移到前面}void DeQueue(Queue *q,ElemType *e) //队头的元素出队存入*e{if(q->rear == q->front) //如果队列为空返回return;*e = q->data[q->front]; //返回队头的元素q->front = (q->front + 1) % MAXSIZE; //游标front向前移一位,如果是队列的末尾移动到最前面}bool IsEmpty(Queue *q) //判断队列是否为空{return q->front == q->rear ? true : false;}int GetQueueLength(Queue *q) //返回队列的长度{return (q->rear - q->front + MAXSIZE) % MAXSIZE;}void Clear(Queue *q) //清空队列{q->front = q->rear = 0;}void Print(Queue *q) //打印队列{if(q->front == q->rear)return;else if(q->rear < q->front){for(int i = q->front;i < MAXSIZE;++i)printf("%d ",q->data[i]);for(int i = 0;i < q->rear;++i)printf("%d ",q->data[i]);printf("\n");}else{for(int i = q->front;i < q->rear;++i)printf("%d ",q->data[i]);printf("\n");}}

#include "Queue.h"#include <stdio.h>int main(){Queue q;InitQueue(&q);for(int i = 1;i < 20;++i)EnQueue(&q,i);Print(&q);int k;DeQueue(&q,&k);EnQueue(&q,30);Print(&q);return 0;}