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Java Collection, TreeSet Exercises: Get the first and last elements in a tree set

Java Collection, TreeSet Exercises: Exercise-5 with Solution

Write a Java program to get the first and last elements in a tree set.

Sample Solution:

Java Code:

import java.util.TreeSet;
  public class Exercise5 {
  public static void main(String[] args) {
  TreeSet<String> tree_set = new TreeSet<String>();
  tree_set.add("Red");
  tree_set.add("Green");
  tree_set.add("Orange");
  tree_set.add("White");
  tree_set.add("Black");
  System.out.println("Tree set: ");
  System.out.println(tree_set);

   // Find first element of the tree set
    Object first_element = tree_set.first();
    System.out.println("First Element is: "+first_element);
 
    // Find last element of the tree set
    Object last_element = tree_set.last();
    System.out.println("Last Element is: "+last_element);
 }
}

Sample Output:

Tree set:                                                              
[Black, Green, Orange, Red, White]                                     
First Element is: Black                                                
Last Element is: White 

Flowchart:

Flowchart: Get the first and last elements in a 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