如何实现Iterable [英] How to implements Iterable

问题描述

在我的程序中，我写了自己的LinkedList类。还有一个实例，llist。

要在foreach循环中使用它，LinkedList需要实现Iterable吗？

<$ （节点节点：llist）{
System.out.print（node.getData（）+）; pre>



$ b $ p
$ b $ p $这里是我的LinkedList类。请让我知道如何使它可以迭代？

  public class LinkedList implements Iterable {
 private Node head = null ; 
 private int length = 0; 
 
 public LinkedList（）{
 this.head = null; 
 this.length = 0; 
} 
 
 LinkedList（节点头）{
 this.head = head; 
 this.length = 1; 
 
 
 LinkedList（LinkedList ll）{
 this.head = ll.getHead（）; 
 this.length = ll.getLength（）; 
 
 $ b $ public void appendToTail（int d）{
 ... 
} 
 
 public void appendToTail（Node node）{
 ... 
} 
 
 public void deleteOne（int d）{
 ... 
} 
 
 public void deleteAll （int d）{
 ... 
} 
 
 public void display（）{
 ... 
} 
 
 public Node getHead（）{
 return head; 
} 
 public void setHead（Node head）{
 this.head = head; 
} 
 public int getLength（）{
 return length; 
} 
 public void setLength（int length）{
 this.length = length; 
 
 $ b public boolean isEmpty（）{
 if（this.length == 0）
 return true; 
返回false; 
 
 
 $ / code $ / pre 
 
解决方案
  Iterable 接口的唯一方法  iterator（） 。
 
 
您将需要返回一个  Iterator  。通常这是通过创建一个实现 Iterator 的内部类，并通过创建该内部类的一个实例来实现 iterator 并返回它。
 
In my program, I write my own LinkedList class. And an instance, llist.

To use it in foreach loop as following, LinkedList needs to implement Iterable?
for(Node node : llist) {
    System.out.print(node.getData() + " ");
}
Here following is my LinkedList class. Please let me know how can I make it Iterable?
public class LinkedList implements Iterable {
    private Node head = null;
    private int length = 0;

    public LinkedList() {
        this.head = null;
        this.length = 0;
    }

    LinkedList (Node head) {
        this.head = head;
        this.length = 1;
    }

    LinkedList (LinkedList ll) {
        this.head = ll.getHead();
        this.length = ll.getLength();
    }

    public void appendToTail(int d) {
        ...
    }

    public void appendToTail(Node node) {
        ...
    }

    public void deleteOne(int d) {
        ...
    }

    public void deleteAll(int d){
        ...
    }

    public void display() {
        ...
    }

    public Node getHead() {
        return head;
    }
    public void setHead(Node head) {
        this.head = head;
    }
    public int getLength() {
        return length;
    }
    public void setLength(int length) {
        this.length = length;
    }

    public boolean isEmpty() {
        if(this.length == 0)
            return true;
        return false;
    }
}

解决方案
Implement the only method of the Iterable interface, iterator().

You will need to return an instance of Iterator in this method.  Typically this is done by creating an inner class that implements Iterator, and implementing iterator by creating an instance of that inner class and returning it.

                        
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