循环队列

#define _CRT_SECURE_NO_DEPRECATE
#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define MaxSize 5
typedef int ElemType;
typedef struct
{
	ElemType data[MaxSize];		//数组、存储MaxSize-1个元素
	int front, rear;		//队列头、队列尾下标
}sqQueue;
//初始化
void InitQueue(sqQueue *Q)
{
	Q->rear = Q->front = 0;
}
//判空
int isEmpty(sqQueue *Q)
{
	if (Q->rear == Q->front)
		return 1;
	else
		return 0;
}
//入队
int EnQueue(sqQueue *Q, ElemType x)
{
	if ((Q->rear + 1) % MaxSize == Q->front)
		return 0;
	Q->data[Q->rear] = x;
	Q->rear = (Q->rear + 1) % MaxSize;
	return 1;
}
//出队
int DeQueue(sqQueue *Q, ElemType *x)
{
	if (Q->rear == Q->front)
		return 0;
	*x = Q->data[Q->front];
	Q->front = (Q->front + 1) % MaxSize;
	return 1;
}

int main()
{
	sqQueue Q;
	int ret;			//返回值
	ElemType element;		//出队元素
	InitQueue(&Q);
	ret = isEmpty(&Q);
	if (ret)
	{
		printf("队列为空\n");
	}
	else
	{
		printf("队列不为空\n");
	}
	EnQueue(&Q, 3);
	EnQueue(&Q, 4);
	EnQueue(&Q, 5);
	ret= EnQueue(&Q, 6);
	//因为队列最大长度为MaxSize-1个元素，因此7入队时失败
	ret = EnQueue(&Q, 7);
	if (ret)
	{
		printf("队列为空\n");
	}
	else
	{
		printf("队列不为空\n");
	}
	ret = DeQueue(&Q, &element);
	if (ret)
	{
		printf("出队成功，元素值为%d\n", element);
	}
	else
	{
		printf("出队失败\n");
	}
	ret = DeQueue(&Q, &element);
	if (ret)
	{
		printf("出队成功，元素值为%d\n", element);
	}
	else
	{
		printf("出队失败\n");
	}
	ret = EnQueue(&Q, 8);
	if (ret)
	{
		printf("入队成功\n");
	}
	else
	{
		printf("入队失败\n");
	}
	system("pause");
}