#include 
    
     #include 
     
      #define M 100int flag=0;typedef struct SqQueue{    char *base;    int front;    int rear;}SqQueue;void InitQueue(SqQueue *Q){    Q->base=(char *)malloc(M*sizeof(char));    if(!Q->base)        exit(-1);    Q->front=Q->rear=0;}void CreateQueue(SqQueue *Q){    int len,i;    char ch;    printf("请输入队长：\n");    scanf("%d",&len);    while(len<1||len>M)    {        printf("输入队长不符合要求，请输入队长：\n");        scanf("%d",&len);    }    for(i=0;i
      
       base[Q->rear++]=ch;    }    flag=1;}void EnQueue(SqQueue *Q){    if((Q->rear+1)%M==Q->front)        printf("队列已满，无法进行入队操作！\n");    else    {        char ch;        printf("请输入如队列元素：\n");        scanf("%c",&ch);        if((ch=getchar())!='\n')        {            Q->base[Q->rear]=ch;            Q->rear=(Q->rear+1)%M;        }    }}void DeQueue(SqQueue *Q){    if(Q->front==Q->rear)        printf("循环队列已空，无法进行出队操作！\n");    else    {        char e=Q->base[Q->front];        Q->front=(Q->front+1)%M;        printf("出队元素为：%c\n",e);    }}int LengthQueue(SqQueue Q){    return (Q.rear+M-Q.front)%M;}void EmptyQueue(SqQueue Q){    if(Q.front==Q.rear)        printf("队列为空！\n");    else        printf("队列不为空！\n");}void DisplayQueue(SqQueue Q){    int i;    if(Q.front==Q.rear)        printf("循环队列为空，不能输出！\n");    else    {        for(i=Q.front;i
       
        base)        printf("循环队列已经被销毁！\n");    else    {        free(Q->base);        Q->front=Q->rear=0;        flag=0;    }}void menu(){    printf("\t循环队列基本实验操作\n");    printf("*********************************\n");    printf("1 建立循环队列！\t\t*\n");    printf("2 循环队列入队操作！\t\t*\n");    printf("3 循环队列出队操作！\t\t*\n");    printf("4 求循环队列长度！\t\t*\n");    printf("5 判断队列是否为空！\t\t*\n");    printf("6 显示队列！\t\t\t*\n");    printf("7 销毁队列！\t\t\t*\n");    printf("0 退出程序！\t\t\t*\n");    printf("*********************************\n");}int main(){    int select;    SqQueue Q;    InitQueue(&Q);    while(1)    {        menu();        printf("请输入要选择的命令：\n");        scanf("%d",&select);        switch(select)        {        case 1:            if(flag==1)                printf("循环链队列已经创建！\n");            else                CreateQueue(&Q);            break;        case 2:            if(flag==0)                printf("循环队列未创建，无法进行如入队操作！\n");            else                EnQueue(&Q);            break;        case 3:            if(flag==0)                printf("循环队列未创建，无法进行如出队操作！\n");            else                DeQueue(&Q);            break;        case 4:            if(flag==0)                printf("循环队列未创建，无法计算队长度！\n");            else                printf("循环队列的长度为：%d\n",LengthQueue(Q));            break;        case 5:            if(flag==0)                printf("循环队列未创建，无法判断队列是否为空！\n");            else                EmptyQueue(Q);            break;        case 6:            if(flag==0)                printf("循环队列未创建，无法显示队列！\n");            else                DisplayQueue(Q);            break;        case 7:            if(flag==0)                printf("循环队列未创建，无法进行销毁队列操作！\n");            else                DestroyQueue(&Q);            break;        case 0:            exit(1);            break;        default :            printf("命令输入有误，请重新输入！\n");            break;        }    }    return 0;}