数据结构.循环队列(C语言实现)
#include<stdio.h>
#include<stdlib.h>
#include<malloc.h>

#define Status int
#define OK 1
#define ERROR 0
#define QElemtype int
#define MAXSIZE 100

typedef struct {
QElemtype *base;
int front;
int rear;
}SqQueue;

/************************************
****** initialize cycle queue
*************************************/
Status InitQueue(SqQueue *Q)
{
Q->base =(QElemtype *)malloc(sizeof(QElemtype) * sizeof(QElemtype));
if (! Q->front)
return ERROR;
Q->front = Q->rear = 0;

return OK;
}

/*************************************
**** QueueLength ************
***************************************/
int Queuelength(SqQueue Q)
{
return (Q.rear - Q.front + MAXSIZE) % MAXSIZE;

}

/*************************************
**** QueueLength ************
***************************************/
void PrintQueue(SqQueue *Q)
{
QElemtype *a = Q->base;

int front = Q->front;
int rear = Q->rear;

while (front != rear)
{
printf("%d\t\n",a[front]);
front++;
}

printf("\n");

}
/*************************************
**** EnQueue ************
***************************************/
Status EnQueue(SqQueue *Q, QElemtype e)
{
if ((Q->rear+1) % MAXSIZE ==Q->front) //cycle Queue is full
return ERROR;

Q->base[Q->rear] = e;
Q->rear = (Q->rear + 1) % MAXSIZE;

return OK;
}

/*************************************
**** DeQueue ************
***************************************/
Status DeQueue(SqQueue *Q, QElemtype e)
{
if (Q->front == Q->rear)
return ERROR;
e = Q->base[Q->front];
printf("deleted %d\n",e);
sleep(1);
Q->front = (Q->front +1) % MAXSIZE;

return OK;
}


int main(void)
{
SqQueue S;
printf("main-begin %p\n",S.base);
InitQueue(&S);

int i = 0;
for(; i < 10; ++i)
{
EnQueue(&S, i);
}
PrintQueue(&S);

for(i=0; i < 5; ++i)
DeQueue(&S,i);
printf("main-end %p\n",S.base);
//free(S.base);
printf("main-end-after free %p\n",S.base);
return OK;

}