linkedLoop

public class linkQueue <E>{
    
    private class Node<E>{
        E e;
        Node<E> next;
        
        public Node(){}
        public Node(E e,Node next){
            this.e=e;
            this.next=next;
        }
        
    }
    
    
    private Node front;
    private Node rear;
    private int size;
    
    public linkQueue(){
        
        front=rear=null;
        
    }
    

    //
    public boolean empty(){
        
        return size==0;
    }
    
    //插入
    public boolean add(E e){
        
        if(empty()){
            
            front=new Node(e,null);
            rear=front;
            
        }
        else{
            
            Node<E> newnode=new Node<E>(e,null);
            rear.next=newnode;
            rear=newnode;
            
            
        }
        size++;
        return true;
        
    }
    
    
    //出队
    public Node poll(){
        
        if(empty()){
            throw new RuntimeException("空队列异常");
        }
        else{
            Node frontnode=front;
            front=front.next;
            frontnode.next=null;
            size--;
            return frontnode;
            
            
        }
    }
    
}