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;
}