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Java Collection, TreeSet Exercises: Create a reverse order view of the elements contained in a given tree set

Java Collection, TreeSet Exercises: Exercise-4 with Solution

Write a Java program to create a reverse order view of the elements contained in a given tree set.

Sample Solution:

Java Code:

import java.util.TreeSet;
import java.util.Iterator;
  public class Exercise4 {
  public static void main(String[] args) {
    // create an empty tree set
     TreeSet<String> t_set = new TreeSet<String>();
   // use add() method to add values in the tree set
          t_set.add("Red");
          t_set.add("Green");
          t_set.add("Black");
          t_set.add("Pink");
          t_set.add("orange");
     // print original list
   System.out.println("Original tree set:" + t_set);  
     Iterator it = t_set.descendingIterator();
     // Print list elements in reverse order
     System.out.println("Elements in Reverse Order:");
     while (it.hasNext()) {
        System.out.println(it.next());
     }
  }
}

Sample Output:

Original tree set:[Black, Green, Pink, Red, orange]                    
Elements in Reverse Order:                                             
orange                                                                 
Red                                                                    
Pink                                                                   
Green                                                                  
Black

Flowchart:

Flowchart: Create a reverse order view of the elements contained in a given tree set

Java Code Editor:

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Java: Tips of the Day

Try and catch:

Java is excellent at catching errors, but it can only recover gracefully if you tell it what to do. The cascading hierarchy of attempting to perform an action in Java starts with try, falls back to catch, and ends with finally. Should the try clause fail, then catch is invoked, and in the end, there's always finally to perform some sensible action regardless of the results. Here's an example:

try {
        cmd = parser.parse(opt, args); 
       
        if(cmd.hasOption("help")) {
                HelpFormatter helper = new HelpFormatter();
                helper.printHelp("Hello ", opt);
                System.exit(0);
                }
        else {
                if(cmd.hasOption("shell") || cmd.hasOption("s")) {
                String target = cmd.getOptionValue("tgt");
                } // else
        } // fi
} catch (ParseException err) {
        System.out.println(err);
        System.exit(1);
        } //catch
        finally {
                new Hello().helloWorld(opt);
        } //finally
} //try

It's a robust system that attempts to avoid irrecoverable errors or, at least, to provide you with the option to give useful feedback to the user. Use it often, and your users will thank you!

Ref: https://red.ht/3EZc9OC