循环队列

问题：主要是队列为空和满的条件.

         为空：cqueue->front==cqueue->rear  为满(cqueue->rear+1)==cqueue->front

代码:

#include <iostream>
#include <cstdlib>
using namespace std;
#define MAXSIZE 20
typedef struct CQueue
{
	int front;
	int rear;
	int data[MAXSIZE];
}*CirQueue;

void initCQueue(CirQueue &cqueue)
{
	cqueue=(CirQueue)malloc(sizeof(struct CQueue));
	if(!cqueue)
	{
		cout<<"allocate fail"<<endl;
		exit(-1);
	}
	else
	{
		cqueue->front=cqueue->rear=0;
	}
}

void enCQueue(CirQueue cqueue,int elem)
{
	if((cqueue->rear+1)%MAXSIZE==cqueue->front)
	{
		cout<<"循环队列已满"<<endl;
		exit(0);
	}
	else
	{
		cqueue->data[cqueue->rear%MAXSIZE]=elem;
		cqueue->rear++;
	}
}

int deCQueue(CirQueue cqueue)
{
	int elem;
	if(cqueue->front==cqueue->rear)
	{
		cout<<"队列已空"<<endl;
		exit(0);
	}
	else
	{
		elem=cqueue->data[cqueue->front%MAXSIZE];
		cqueue->front++;
	}
	return elem;
}

int main()
{
	CirQueue cqueue;
	int arr[]={1,2,3,4,5,6,7,9,0};

	initCQueue(cqueue);

	cout<<"循环队列入队:1 2 3 4 5 6 7 9 0:"<<endl;  
	for(int i=0;i<9;i++)
	{
		enCQueue(cqueue,arr[i]);
	}

	cout<<"循环队列出队:"<<endl;
	while(cqueue->front!=cqueue->rear)
	{
	    cout<<deCQueue(cqueue)<<"  ";
	}
	cout<<endl;
	return 0;
}

运行结果: