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Java program to iterate TreeSet collection in descending order

Given a TreeSet collection, we have to iterate it in descending order.
Submitted by Nidhi, on June 06, 2022

Problem Solution:

In this program, we will create a TreeSet collection with integer elements. Then we will use the descendingIterator() method to iterate created TreeSet collection in the descending order.

Program/Source Code:

The source code to iterate the TreeSet collection in descending order is given below. The given program is compiled and executed successfully.

Example of TreeSet.descendingIterator() Method in Java

// Java program to iterate TreeSet collection 
// in descending order

import java.io.*;
import java.util.*;

public class Main {
  public static void main(String args[]) {
    TreeSet < Integer > tree = new TreeSet < Integer > ();

    tree.add(25);
    tree.add(20);
    tree.add(35);
    tree.add(30);

    Iterator < Integer > iterator = tree.descendingIterator();

    System.out.println("Elements in descending order:");

    while (iterator.hasNext()) {
      System.out.println("Value : " + iterator.next());
    }
  }
}

Output:

Elements in descending order:
Value : 35
Value : 30
Value : 25
Value : 20

Explanation:

In the above program, we imported the "java.util.*", "java.io.*" packages to use the TreeSet class. Here, we created a public class Main.

The Main class contains a main() method. The main() method is the entry point for the program. And, created a TreeSet collection tree and added integer elements using add() method. Then we used the descendingIterator() method to get elements of the TreeSet collection and printed them in the descending order.

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