第三章 栈和队列 —— 循环队列

循环队列

注意：

代码如下：

#include <iostream>
#include <stdlib.h>

#define MAXQSIZE 100
#define OK 1
#define ERROR 0
#define OVERFLOW -1

typedef int QElemType_CSq;
typedef int Status;

using namespace std;
//定以队列的顺序存储结构
typedef struct
{
    QElemType_CSq *base;//用于动态分配空间
    int front;//队头索引
    int rear;//队尾索引
}CSqQueue;

//初始化
Status InitQueue_CSq(CSqQueue &Q)
{
    Q.base = (QElemType_CSq *)malloc(MAXQSIZE*sizeof(QElemType_CSq));
    if (!Q.base)
        exit(OVERFLOW);
    Q.front = Q.rear = 0;
    return OK;
}

//入队
Status EnQueue_CSq(CSqQueue &Q)
{
    int n,e;
    cout<<"请输入要入队的元素个数："<<endl;
    cin>>n;
    cout<<"请依次输入要入队的元素："<<endl;
    for (int i=0;i<n;i++)
    {
        cin>>e;
        if ((Q.rear + 1)%MAXQSIZE == Q.front)
        {
            cout<<"循环队列已满"<<endl;
            return ERROR;
        }
        Q.base[Q.rear] = e;
        Q.rear = (Q.rear+1)%MAXQSIZE;
    }
    cout<<"入队成功"<<endl;
    return OK;
}

//显示循环队列
void QueueTraverse_CSq(CSqQueue Q)
{
    int i = Q.front;
    cout<<"循环队列内元素为："<<endl;
    while (i!=Q.rear)
    {
        cout<<Q.base[i]<<" ";
        i = (i+1)%MAXQSIZE;
    }
    cout<<endl;
}

//清空循环队列
void ClearQueue_CSq(CSqQueue &Q)
{
    Q.front = Q.rear = 0;
    cout<<"清空成功"<<endl;
}

//判断队列是否为空
void QueueEmpty_CSq(CSqQueue Q)
{
    if (Q.front == Q.rear)
        cout<<"队列为空"<<endl;
    else
        cout<<"队列不为空"<<endl;
}

//求循环队列长度
int QueueLength_CSq(CSqQueue Q)
{
    return (Q.rear-Q.front+MAXQSIZE)%MAXQSIZE;
}

//取队头元素
Status GetHead_CSq(CSqQueue Q)
{
    int e;
    if (Q.front == Q.rear)
    {
        cout<<"队列为空，无队头元素"<<endl;
        return ERROR;
    }
    e = Q.base[Q.front];
    cout<<"队头元素为："<<e<<endl;
    return OK;
}

//出队
Status DeQueue_CSq(CSqQueue &Q)
{
    if (Q.front == Q.rear)
    {
        cout<<"队列为空，无法出队"<<endl;
        return ERROR;
    }
    int e;
    e = Q.base[Q.front];
    Q.front = (Q.front+1)%MAXQSIZE;
    cout<<"队头元素"<<e<<"出队成功"<<endl;
    return OK;
}

void show_help()
{
    cout<<"******* Data Structure ******"<<endl;
    cout<<"1----清空循环队列"<<endl;
    cout<<"2----判断循环队列是否为空"<<endl;
    cout<<"3----求循环队列长度"<<endl;
    cout<<"4----获取队头元素"<<endl;
    cout<<"5----入队"<<endl;
    cout<<"6----出队"<<endl;
    cout<<"7----显式循环队列"<<endl;
    cout<<"     退出，输入0"<<endl;

}
int main()
{
    int operate_code;
    show_help();
    CSqQueue Q;
    InitQueue_CSq(Q);
    while(1)
    {
        cout<<"";
        cin>>operate_code;
        if(operate_code==1)
        {
            ClearQueue_CSq(Q);
        }
        else if (operate_code==2)
        {
            QueueEmpty_CSq(Q);
        }
        else if (operate_code==3)
        {
            cout<<"循环队列的长度为："<<QueueLength_CSq(Q)<<endl;
        }
        else if (operate_code==4)
        {
            GetHead_CSq(Q);
        }
        else if (operate_code==5)
        {
            EnQueue_CSq(Q);
        }
        else if (operate_code==6)
        {
            DeQueue_CSq(Q);
        }
        else if (operate_code==7)
        {
            QueueTraverse_CSq(Q);
        }
        else if (operate_code==0)
        {
            break;
        }
        else
        {
            cout<<"\n操作码错误！！！"<<endl;
            show_help();
        }
    }
    //调用销毁线性表函数，如Destroy_List(L);
    return 0;
}