循环队列的初始化到清空

头文件：

#ifndef _SEQUENCEQUEUE_H
#define _SEQUENCEQUEUE_H

#include <stdio.h>
#include <stdlib.h>

#define SIZE    10

#define SUCCESS   10000
#define FAILURE   10001
#define TRUE      10002
#define FALSE     10003

struct queue
{
	int data[SIZE];
	int front;            //队头指针（下标）
	int rear;             //队尾指针
};
typedef struct queue Queue;

int InitQueue(Queue *q);
int EnterQueue(Queue *q, int e);
int EmptyQueue(Queue q);
int GetFront(Queue q);
int LengthQueue(Queue q);
int DeleteQueue(Queue *q);
int ClearQueue(Queue *q);

#endif

子函数：

#include "SequenceQueue.h"

int InitQueue(Queue *q)
{
	if (NULL == q)
	{
		return FAILURE;
	}

	q->rear = q->front = 0;   //初始化空队

	return SUCCESS;
}

int EmptyQueue(Queue q)
{
	return (q.front == q.rear) ? TRUE : FALSE;
}

int EnterQueue(Queue *q, int e)
{
	if (NULL == q)
	{
		return FAILURE;
	}

	if ((q->rear + 1) % SIZE == q->front)   //队满
	{
		return FAILURE;
	}

	q->data[q->rear] = e;
	q->rear = (q->rear + 1) % SIZE;

	return SUCCESS;
}

int GetFront(Queue q)
{
	if (q.rear == q.front)
	{
		return FAILURE;
	}

	return q.data[q.front];
}

int LengthQueue(Queue q)
{
	return (q.rear - q.front + SIZE) % SIZE;
}

int DeleteQueue(Queue *q)
{
	if (NULL == q)
	{
		return FAILURE;
	}
	if (q->rear == q->front)
	{
		return FAILURE;
	}

	int e = q->data[q->front];
	q->front = (q->front + 1) % SIZE;

	return e;
}

int ClearQueue(Queue *q)
{
	if (NULL == q)
	{
		return FAILURE;
	}

	q->front = q->rear;

	return SUCCESS;
}

测试主函数：

#include "SequenceQueue.h"

int main()
{
	int ret, i;
	Queue queue;

	ret = InitQueue(&queue);
	if (ret == SUCCESS)
	{
		printf("Init Success!\n");
	}
	else
	{
		printf("Init Failure!\n");
	}

	ret = EmptyQueue(queue);
	if (ret == TRUE)
	{
		printf("Queue Is Empty!\n");
	}
	else
	{
		printf("Queue is not Empty!\n");
	}
	
	for(i = 0; i < 10; i++)
	{
		ret = EnterQueue(&queue, i);
		if (FAILURE == ret)
		{
			printf("Enter %d Failure!\n", i);
		}
		else
		{
			printf("Enter %d Success!\n", i);
		}
	}

	ret = GetFront(queue);
	if (ret == FAILURE)
	{
		printf("Get Front Failure!\n");
	}
	else
	{
		printf("Front is %d\n", ret);
	}

	ret = LengthQueue(queue);
	printf("length is %d\n", ret);

	for (i = 0; i < 5; i++)
	{
		ret = DeleteQueue(&queue);
		if (ret == FAILURE)
		{
			printf("Delete Failure!\n");
		}
		else
		{
			printf("Delete %d Success!\n", ret);
		}
	}

	ret = ClearQueue(&queue);
	if (ret == SUCCESS)
	{
		printf("Clear Success!\n");
	}
	else
	{
		printf("Clear Failure!\n");
	}

	ret = GetFront(queue);
	if (ret == FAILURE)
	{
		printf("Get Front Failure!\n");
	}
	else
	{
		printf("Front is %d\n", ret);
	}

	return 0;
}