队列-银行叫号系统

通过队列实现银行叫号，可以显示当前排队序号和叫号功能

#include<stdio.h>
#include<stdlib.h>
#define OK 1
#define ERROR 0
#define TRUE 1
#define FALSE 0
#define OVERFLOW -1
typedef int Status;
typedef int ElemType;
typedef struct QNode
{
ElemType data;
struct QNode *next;
} QNode,*QueuePtr;
typedef struct
{
QueuePtr front; //队头指针
QueuePtr rear; //队尾指针
} LinkQueue;

Status InitQueue(LinkQueue &Q) //构造一个空队列Q
{
Q.front = Q.rear = (QueuePtr)malloc(sizeof(QNode));
if(!Q.front)
exit(OVERFLOW);
Q.front->next = NULL;
return OK;
}

Status DestroyQueue(LinkQueue &Q) //销毁队列Q
{
while(Q.front)
{
Q.rear = Q.front->next;
free(Q.front);
Q.front = Q.rear;
}
return OK;
}

Status ClearQueue(LinkQueue &Q) //将Q清为空队列
{
QueuePtr p,q;
p = Q.front->next;
while§
{
q = p->next;
free§;
p = q;
}
Q.rear = Q.front;
Q.front->next = NULL;
return OK;
}

Status QueueEmpty(LinkQueue Q) //若队列Q为空队列，则返回TURE,否则返回FALSE
{
if(Q.front == Q.rear)
return TRUE;
else
return FALSE;
}

int QueueLength(LinkQueue Q) //返回Q的元素个数，即为队列的长度
{
QueuePtr p;
int length = 0;
p = Q.front->next;
while§
{
length ++;
p = p->next;
}
return length;
}

Status GetHead(LinkQueue Q, ElemType &e) //若队列不空，则用e返回Q的队头元素，并返回OK，否则返回ERROR
{
QueuePtr p;
//if(Q.front == Q.rear)
// return ERROR;
p = Q.front->next;
if§
{
e = p->data;
return OK;
}
return ERROR;
}

Status EnQueue(LinkQueue &Q, ElemType e) //插入元素e为Q的新的队尾元素
{
QueuePtr p = (QueuePtr)malloc(sizeof(QNode));
if(!p)
exit(OVERFLOW);
p->data = e;
p->next = NULL;
Q.rear->next = p;
Q.rear = p;
return OK;
}

Status DeQueue(LinkQueue &Q, ElemType &e) //若队列不空，则删除Q的队头元素，用e返回其值，并返回OK，否则返回ERROR
{
if(Q.front == Q.rear)
return ERROR;
QueuePtr p;
p = Q.front->next;
e = p->data;
Q.front->next = p->next;
if(p == Q.rear)
Q.rear = Q.front;
free§;
return OK;
}

Status QueueTraverse(LinkQueue Q) //从队头到队尾依次对队列Q中每个函数调用visit().一旦visit（）失败，操作失败
{
QueuePtr p;
p = Q.front->next;
while§
{
printf("%d “,p->data);
p = p->next;
}
printf(”\n");
return OK;
}

int main(void)
{
LinkQueue Q;
int slt;
ElemType e;
int sum = 0;
InitQueue(Q);

printf("欢迎进入银行叫号系统模式\n");
while(1)
{
    printf("1. 排号\n");
    printf("2. 叫号\n");
    printf("0. 退出系统\n");
    printf("\n");
    printf("请输入你的选择：\n");
    scanf("%d", &slt);
    printf("\n");
    if( slt == 0)
        break;
    switch(slt)
    {
    case 2:
        if(QueueEmpty(Q))   //判断队列是否为空
            printf("输入错误，此时无人排队\n\n");
        else
        {
            GetHead(Q,e);
            printf("请%d号到窗口办理业务\n",e);
            DeQueue(Q,e);   //若队列不空，则删除Q的队头元素，用e返回其值，并返回OK，否则返回ERROR
            printf("\n");
        }
        break;

    case 1:
        EnQueue(Q,++sum);   //插入元素e为Q的新的队尾元素
        printf("您的序号是%d，您前面有人%d等候\n",sum,QueueLength(Q)-1);
        printf("\n");
        break;
    }
}
printf("\n感谢您使用银行叫号系统\n");
return 0;

}