ArrayDeque descendingIterator() Method in Java

Last Updated : 10 Dec, 2018

The Java.util.ArrayDeque.descendingIterator() method is used to return an iterator of the same elements as the ArrayDeque but in the reverse order.

Syntax:

Iterator iterate_value = Array_Deque.descendingIterator();

Parameters: The method does not take any parameter.

Return Value: The method iterates over the elements of the deque and returns the values(iterators) in reverse order.

Below programs illustrate the Java.util.ArrayDeque.descendingIterator() method:
Program 1:

// Java code to illustrate descendingIterator()
import java.util.*;
  
public class ArrayDequeDemo {
    public static void main(String args[])
    {
        // Creating an empty ArrayDeque
        Deque<String> de_que = new ArrayDeque<String>();
  
        // Use add() method to add elements into the Queue
        de_que.add("Welcome");
        de_que.add("To");
        de_que.add("Geeks");
        de_que.add("4");
        de_que.add("Geeks");
  
        // Displaying the ArrayDeque
        System.out.println("ArrayDeque: " + de_que);
  
        // Creating a desc_iterator
        Iterator value = de_que.descendingIterator();
  
        // Displaying the values after iterating through the Deque
        // in reverse order
        System.out.println("The iterator values are: ");
        while (value.hasNext()) {
            System.out.println(value.next());
        }
    }
}

Output:

ArrayDeque: [Welcome, To, Geeks, 4, Geeks]
The iterator values are: 
Geeks
4
Geeks
To
Welcome

Program 2:

// Java code to illustrate descendingIterator()
import java.util.*;
  
public class ArrayDequeDemo {
    public static void main(String args[])
    {
        // Creating an empty ArrayDeque
        Deque<Integer> de_que = new ArrayDeque<Integer>();
  
        // Use add() method to add elements into the Queue
        de_que.add(10);
        de_que.add(15);
        de_que.add(30);
        de_que.add(20);
        de_que.add(5);
  
        // Displaying the ArrayDeque
        System.out.println("ArrayDeque: " + de_que);
  
        // Creating a desc_iterator
        Iterator value = de_que.descendingIterator();
  
        // Displaying the values after iterating through the Deque
        // in reverse order
        System.out.println("The iterator values are: ");
        while (value.hasNext()) {
            System.out.println(value.next());
        }
    }
}

Output:

ArrayDeque: [10, 15, 30, 20, 5]
The iterator values are: 
5
20
30
15
10

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