环形队列

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#include <stdio.h>
#include <malloc.h>
#define MaxSize 100
typedef char ElemType;
typedef struct
{
	ElemType data[MaxSize];				//数据域
	int front,rear;	//指针域
} SqQueue;						//链栈类型定义
void InitQueue(SqQueue *&q)
{
	q=(SqQueue *)malloc(sizeof(SqQueue));
	q->front=q->rear=0;
}
void DestoryQueue(SqQueue *&q)
{
	free(q);
}
int QueueEmpty(SqQueue *q)
{
	return(q->front==q->rear);
}
int enQueue(SqQueue *&q,ElemType e)
{
    if((q->rear+1)%MaxSize==q->front)
        return 0;
        q->rear=(q->rear+1)%MaxSize;
        q->data[q->rear]=e;
        return 1;
}
int deQueue(SqQueue *&q,ElemType &e)
{

    if(q->rear==q->front)
        return 0;
    q->front=(q->front+1)%MaxSize;
    e=q->data[q->front];
    return 1;
}
int countQueue(SqQueue *&q)
{
    return((q->rear-q->front+MaxSize)%MaxSize);
}
int main()
{
    SqQueue *q;
    ElemType e;
    printf("(1)初始化队列q\n");
    InitQueue(q);
    printf("(2)队为:%s\n",(QueueEmpty(q)?"空":"非空"));
    printf("(3)依次进队元素a,b,c");
    enQueue(q,'a');
    enQueue(q,'b');
    enQueue(q,'c');
    printf("\n(4)出队一个元素：");
    deQueue(q,e);
    printf("%c",e);
    printf("\n(5)q队中元数个数：%d", countQueue(q));
    printf("\n(6)再依次进队元素d,e,f");
    enQueue(q,'d');
    enQueue(q,'e');
    enQueue(q,'f');
    printf("\n(7)q队中元数个数：%d", countQueue(q));
    printf("\n(8)出队全部元素：");
    while(!QueueEmpty(q))
    {
        deQueue(q,e);
        printf("%c",e);
    }
    printf("\n(9)销毁队列");
    DestoryQueue(q);
    return 0;
}