实验1.1  环形队列
一、    实验目的
掌握环形队列顺序结构的概念，理解环形队列的基本运算。
二、    实验内容
1、    删除环形队列第k个元素
编写算法的要求：从键盘输入被删除元素的位置k,由x返回该元素值，并输出队列中元素的个数。
请将上述编好的函数插入相应的实验框架程序，并调试运行，分析实验结果。
三、    环形队列实验程序
    #include<iostream.h>
#define max 15
const int m = max+1;

struct cqueue{
    int e[max];
    int front,rear;
};

void setnull(cqueue &cq)  //置环形队列cq为空
{
    cq.front = 0;
    cq.rear = 0;
}

void create(cqueue &cq)  //输入环形队列cq元素的值
{
    int d;
    cout<<"INPUT DATA(END -1):\n\t";
    cout<<"DATA:";
    cin>>d;
    while (d != -1){
        cq.e[cq.rear] = d;
        cq.rear = (cq.rear + 1) % m;
        cin>>d;
    }
}

void outcq(cqueue cq)  //输出环形队列cq中元素的值  
{   
    int i;
    i = cq.front;
    while (i != cq.rear ){
        cout<<cq.e[i]<<'\t';
        i = (i + 1) % m;
    }
    cout<<'\n';
}

void error(char err[])  //输出出错信息
{
    cout<<err<<"出错\n";
}

void insert_cqueue(cqueue &cq,int x)
  //入队算法
{
    int p;
    p = cq.rear;
    cq.rear = (cq.rear + 1) % m;
    if (cq.front == cq.rear){
        cq.rear = p;
        error("err1");//环形队列满出错
    }
    else cq.e[p] = x;
}

void delete_cqueue(cqueue &cq,int &x)
  //出队算法
{
    if (cq.front == cq.rear)
        error("err2");//环形队列空出错
    else {
          x = cq.e[cq.front];
          cq.front = (cq.front + 1) % m;
         }
}

int length(cqueue cq)
  //求环形队列cq长度函数
{
    int len;
    len = (m + cq.rear - cq.front) % m;   
    return len;
}

int empty(cqueue cq)
  //判环形队列cq是否为空函数
{
    int emp;
    emp = cq.rear == cq.front;
    return emp;
}

void delelemk(cqueue &cq,int k,int &x)
  //算法功能删除队列cq第i个元素,其值由x返回
{
   


           
}

void main(void)
{
    cqueue cq;
    char c;
    int k,x;
    cout<<" * * * THE PROGRAM FOR CQUEUE * * *\n";
    setnull(cq);
    create(cq);
    do{
        cout<<"TO SELECT COMMAND(I,D,O,K,E)\n\t";
        cout<<"COMMAND:";cin>>c;
        switch(c){
            case 'I':cout<<"TO INSERT NEW ELEMENT IN THE CQUEUE cq\n";
                     cout<<"VALUE OF NEW ELEMENT(x) = ";
                     cin>>x;
                     insert_cqueue(cq,x);
                     outcq(cq);
                     break;
            case 'D':cout<<"TO DELETE ELEMENT IN THE CQUEUE cq\n";
                     delete_cqueue(cq,x);
                     outcq(cq);
                     break;
            case 'O':cout<<"ELEMENT OF THE CQUEUE cq READS AS FOLLOWS:\n";
                     outcq(cq);
                     break;
            case 'K':cout<<"TO DELETE ELEMENT ON NUMBER SEQUENCE k IN THE CQUEUE cq\n";
                     cout<<"NUMBER SEQUENCE OF THE ELEMENT(k) = ";
                     cin>>k;
                     delelemk(cq,k,x);
                     outcq(cq);
                     break;
            case 'E':break;
            default:error("命令字");
        }
    }
    while(c != 'E');   
}