基于学习链表队列的实现

Question

我目前在一个数据结构类中，我的基于链表队列的实现项目遇到了一些麻烦-我已经构建了所有的东西，但我的新的lined-List实例并没有告诉我向"llq"；我创建的实例。下面是我的LinkedList类和Driver类。

请善良！这个特定的主题有点迷失了——我愿意接受任何和所有的反馈——谢谢！

import java.util.LinkedList;
public class LinkedListQueue {
//Declaring Linked List, Node Head & Tail
LinkedList<String> list; 
Node head;
Node tail;
class Node{
int data;
Node prev;
Node next;
/**
* Node Constructor
* @param data
*/
Node(int d){
data = d;
}
}
/**
* Linked List Queue Parameterized Constructor
* @param list
*/
public LinkedListQueue(){
list = new LinkedList<String>();
}
/**
* Enqueue Method (adds element to tail)
* @param list
* @return add
*/
public void enqueue(String string){
list.add(string);
}
/**
* Dequeue Method (removes first element)
* @param list
* @return removeFirst
*/   
public void dequeue(){
if(list.isEmpty()){   /*check if linked list is empty*/
System.out.println("The Queue is Empty.");
}
else {
list.removeFirst();    /*remove first element of linked list*/
}
}
/**
* Size Method (Size of queue)
* @param list
* @return size
*/ 
public int size(){
return list.size();    
}
/**
* Display Method (prints element in queue)
* @param list
* @return prints element at the indicated index
*/ 
public void display(){
for(int i=0;i< list.size();i++){     
System.out.print(list.get(i)+"  ");   
}
System.out.println("n");
}
/**
* getHead Method (gets head of the queue)
* @param list
* @return first element
*/ 
public String getHead(){
if(list.isEmpty()){
return "The Queue is Empty.";
}
else {
return list.getFirst();
}
}
/**
* getTail Method (gets tail of the queue)
* @param list
* @return last element
*/ 
public String getTail(){
if(list.isEmpty()){
return "The Queue is Empty.";
}
else {
return list.getLast();
}
}
/**
* IsEmpty Method (checks if queue is empty)
* @param list
* @return true/false
*/
public boolean isEmpty(){
if(list.isEmpty()){     /*checks if linked list is empty*/
return true;
}
else{
return false;
}
}
/**
* Delete Queue Method (clears queue)
* @param list
* @return clear
*/ 
public void deleteQueue() {
list.clear();
}
}

import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.Queue;

public class Driver{
public static void main(String[] args){
//New instance of linked list queue
LinkedList llq =new LinkedList();
//Checking if stack is empty
System.out.println("Is the Queue empty? " + llq.isEmpty());

llq.addFirst("Queue Element 1");  

llq.enqueue("Queue Element 2");
llq.enqueue("Queue Element 3");
llq.enqueue("Queue Element 4");
llq.enqueue("Queue Element 5");
System.out.println("The element at the head is: " + llq.getHead());

System.out.println("The element at the tail is: " + llq.getTail());

//Checking size of stack
System.out.println("Size of the Queue: " + llq.size());

//Printing Stack
System.out.println("*****Display the Queue*****" );
llq.display();

llq.addLast("Queue Element 6");  
llq.dequeue("Queue Element 2");
llq.dequeue("Queue Element 3");
//Printing Stack
System.out.println("*****Display the Queue*****" );
llq.display();

llq.dequeue("Queue Element 6");  
llq.dequeue("Queue Element 7");  


//Checking if stack is empty
System.out.println("Is the stack empty? " + llq.isEmpty());

//Clearing Stack
llq.deleteQueue();

//Checking if stack is empty
System.out.println("Is the stack empty? " + llq.isEmpty());
}
}

Answer 1

应该是

LinkedListQueue llq = new LinkedListQueue();

相反，因为你不想要一个普通的LinkedList，而是你自己的包装。