class Element{

    int id;

    String name;

    Element(int a,String n){

        id=a;name=n;

    }

}

class SeqQueue{

    int first,last,maxsize;

    Element queue[];

    SeqQueue(int i){

        maxsize=i;

        first=last=-1;

        queue=new Element[i];

    }

    public void clear(){//置空

        first=last=-1;

    }

    public boolean isEmpty(){//判空

        if(first==-1)return true;

        else return false;

    }

    public Element getFirst(){//取队列头元素

        if(first==-1)return null;

        else return queue[first+1];

    }

    public boolean isFull(){//判满

        if((last+1)%maxsize==first)return true;

        else return false;

    }

    public boolean enQueue(Element e){//入队

        if(this.isFull())return false;

        if(this.isEmpty())

            first=last=0;

        else

            last=(last+1)%maxsize;

        queue[last]=e;

        return true;

    }

    public Element deQueue(){//出队

        Element t=queue[first];

        if(this.isEmpty())return null;

        if(first==last){

            queue[first]=null;

            this.clear();

            return t;

        }

        queue[first]=null;

        first=(first+1)%maxsize;

        return t;

    }

    public int getLength(){//队列长度

        if(last>=first)return last-first+1;

        else return maxsize-(first-last)+1;

    }

    public void display(){//打印所有元素

        int i,j;

        for (i=first,j=0;j<this.getLength();i=(i+1)%maxsize,j++)

            System.out.println(queue[i].id);

    }

}