Java LinkedList descendingIterator()方法及示例

java.util.LinkedList 类的 descendingIterator() 方法用于返回该LinkedList中元素的反向顺序的迭代器。这些元素将按照从最后一个（尾部）到第一个（头部）的顺序返回。

语法

public Iterator descendingIterator()

返回值： 该方法以反向顺序返回该LinkedList中的元素的 迭代器 。

以下是说明descendingIterator()方法的例子

例1 :

// Java program to demonstrate
// descendingIterator() method
// for String value
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
  
        try {
  
            // creating object of TreeMap<Integer, String>
            LinkedList<String> list = new LinkedList<String>();
  
            // add some elements to list
            list.add("A");
            list.add("B");
            list.add("C");
  
            // print the linked list
            System.out.println("LinkedList:" + list);
  
            // set Iterator as descending
            // using descendingIterator() method
            Iterator x = list.descendingIterator();
  
            // print list with descending order
            while (x.hasNext()) {
                System.out.println("Value is : "
                                   + x.next());
            }
        }
  
        catch (NullPointerException e) {
            System.out.println("Exception thrown : "
                               + e);
        }
    }
}

输出:

LinkedList:[A, B, C]
Value is : C
Value is : B
Value is : A

例2 :

// Java program to demonstrate
// descendingIterator() method
// for Integer value
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
  
        try {
  
            // creating object of TreeMap<Integer, String>
            LinkedList<Integer>
                list = new LinkedList<Integer>();
  
            // add some elements to list
            list.add(10);
            list.add(20);
            list.add(30);
  
            // print the linked list
            System.out.println("LinkedList:" + list);
  
            // set Iterator as descending
            // using descendingIterator() method
            Iterator x = list.descendingIterator();
  
            // print list with descending order
            while (x.hasNext()) {
                System.out.println("Value is : "
                                   + x.next());
            }
        }
  
        catch (NullPointerException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出:

LinkedList:[10, 20, 30]
Value is : 30
Value is : 20
Value is : 10