#include <iostream>

using namespace std;

 #define QueueSize 100
 typedef char DataType;
 typedef struct{
     int front;
     int rear;
     int count;
     DataType data[QueueSize]; 
 }CirQueue;
 
 void InitQueue(CirQueue *Q)
 {//置队空 
     Q->front = Q->rear = 0;
     Q->count = 0;
 } 
 
 int QueueEmpty(CirQueue *Q)
 {//判队空 
     return Q->count == 0;
 }
 
 int QueueFull(CirQueue *Q)
 {//判队满 
     return Q->count == QueueSize;
 } 
 
 void EnQueue(CirQueue *Q, DataType x)
 {//入队 
     if (QueueFull((Q)))
         perror("Queue overflow");
     Q->count ++;
     Q->data[Q->rear] = x;
     Q->rear = (Q->rear + 1)%QueueSize;
 } 
 
 DataType DeQueue(CirQueue *Q)
 {//出队 
     DataType temp;
     if (QueueEmpty((Q)))
         perror("Queue underflow");
     temp = Q->data[Q->front];
     Q->count --;
     Q->front = (Q->front+1)&QueueSize;
     return temp;
 } 
 
 DataType QueueFront(CirQueue *Q)
 {//取队头元素 
     if (QueueEmpty((Q)))
         perror("Queue is empty.");
     return Q->data[Q->front];    
 } 
 
 
 int main()
 {
     CirQueue *Q;
     EnQueue(Q, 'a');
     //EnQueue(Q, 'b');
     //DeQueue(Q);
     cout << QueueFront(Q);
     
     
     return 0;
 }