ArrayDeque descendingIterator() Method in Java (original) (raw)

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 `

// Java code to illustrate descendingIterator() import java.util.*;

public class ArrayDequeDemo { public static void main(String args[]) { // Creating an empty ArrayDeque Deque de_que = new ArrayDeque();

    // 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 `

// Java code to illustrate descendingIterator() import java.util.*;

public class ArrayDequeDemo { public static void main(String args[]) { // Creating an empty ArrayDeque Deque de_que = new ArrayDeque();

    // 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