Java ArrayDeque descendingIterator()方法

java.util.ArrayDeque.descendingIterator() 此方法以相反的顺序返回此双端队列中的元素的迭代器。

1 语法

public Iterator<E> descendingIterator()

2 参数

无

3 返回值

此方法以相反的顺序在此双端队列中的元素上返回迭代器。

4 示例 

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 *  java.util.ArrayDeque.descendingIterator()方法的例子
 */
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Iterator;

public class Demo {
    public static void main(String[] args) {

        // create an empty array deque with an initial capacity
        Deque<Integer> deque = new ArrayDeque<Integer>(8);

        // use add() method to add elements in the deque
        deque.add(15);
        deque.add(22);
        deque.add(25);
        deque.add(20);

        //iterator() is used to print all the elements
        //next() returns the next element on each iteration
        System.out.println("printing elements using iterator:");

        for(Iterator itr = deque.iterator();itr.hasNext();)  {
            System.out.println(itr.next());
        }

        //descendingIterator() is used to print the elements in reverse order
        //next() returns the next element on each iteration
        System.out.println("printing elements in reverse order:");

        for(Iterator descItr = deque.descendingIterator();descItr.hasNext();) {
            System.out.println(descItr.next());
        }
    }
}

输出结果为：

printing elements using iterator:
15
22
25
20
printing elements in reverse order:
20
25
22
15