请问这串代码错在什么地方

#include<iostream>
#include<stdio.h>
using namespace std;
enum  Error_code{underflow, overflow, success};
const int maxqueue =1000; //  small value for testing
typedef double Queue_entry;
class CirQueue {
public:
   CirQueue();
   bool empty() const;
   Error_code serve();
   Error_code append(const Queue_entry &item);
   Error_code retrieve(Queue_entry &item) const;
   bool full() const;
   int size() const;
   void clear();
   Error_code serve_and_retrieve(Queue_entry &item);
private:
   int count;
   int front, rear;
   Queue_entry entry[maxqueue];
};
CirQueue::CirQueue()
{
   count = 0;
   rear = maxqueue - 1;
   front = 0;
}

bool CirQueue::empty() const
{
   return count == 0;
}
Error_code CirQueue::append(const Queue_entry &item)
{
   if (count >= maxqueue) return overflow;
   count++;
   rear = ((rear + 1) == maxqueue) ? 0 : (rear + 1); //处理队尾的下标
   entry[rear] = item;
   return success;
}
Error_code CirQueue::serve()
{
   if (count <= 0) return underflow;
   count--;
   front = ((front + 1) == maxqueue) ? 0 : (front + 1);
   return success;
}
Error_code CirQueue::retrieve(Queue_entry &item) const
{
   if (count <= 0) return underflow;
   item = entry[front];
   return success;
}
int CirQueue::size() const

{
   return count;
}
bool CirQueue::full() const
{
  return(count==maxqueue);
}
void CirQueue::clear()
{
   count = 0;
   rear = maxqueue-1;
   front = 0;
}
Error_code CirQueue::serve_and_retrieve(Queue_entry &item)
{
      if (count <= 0) return underflow;
         item = entry[front];
         count--;
         front = ((front + 1) == maxqueue) ? 0 : (front + 1);
         return success;
}

int main()
{

   double item;
   CirQueue numbers;
   cin>>item;

     while(item!=-1){
        numbers.append(item);
        cin>>item;
     }
     while (!numbers.empty()) {
      numbers.serve_and_retrieve(item);
      cout << item << " ";
   }
   cout << endl;
   return 0;
}