All conditions are met and the code is working fine.

Question about the task

Set of cats

Java Syntax, Level 8, Lesson 11

Resolved

All conditions are met and the code is working fine. What is wrong with the validator?

1. Inside the Solution class, create a public static Cat class.
2. Implement the createCats method. It must create a Set of cats and add 3 cats to it.
3. In the main method, remove one cat from Set cats.
4. Implement the printCats method. It should display all the cats that remain in the set.
Each cat on a new line.

Requirements:

The program should display text on the screen.
Inside the Solution class, there must be a public static Cat class with a default constructor.
The Solution class's createCats() method must return a Set containing 3 cats.
The Solution class's printCats() method must display all the cats in the set. Each cat on a new line.
The main() method should call the createCats() method once.
The main() method should call the printCats() method.
The main() method must remove one cat from the set of cats.

package com.codegym.task.task08.task0819; import java.util.HashSet; import java.util.Iterator; import java.util.Set; /* Set of cats */ public class Solution { public static void main(String[] args) { Set<Cat> cats = createCats(); Iterator<Cat> it = cats.iterator(); while (it.hasNext()) if (it.next().name == "Tom") it.remove(); printCats(cats); } public static Set<Cat> createCats() { HashSet<Cat> catSet = new HashSet<>(); Cat tom = new Cat(); tom.name = "Tom"; Cat alisa = new Cat(); alisa.name = "Alisa"; Cat marusia = new Cat(); marusia.name = "Marusia"; catSet.add(tom); catSet.add(alisa); catSet.add(marusia); return catSet; } public static void printCats(Set<Cat> cats) { for (Cat cat:cats) { System.out.println(cat); //System.out.println("Cat's name: " + cat.name); } } public static class Cat { String name; // public Cat(String xname){ // name = xname; // } } }

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Dmitri

Level 22 , Seversk, Russia

1 November 2020, 06:03

ok, I had to make my code worse - while (it.hasNext()) { it.next(); it.remove(); break; } and the validator acceped.

Nouser

Level 36 , Germany

1 November 2020, 11:54

Your problem probably was the usage of an if condition and the way the validator works. It just sees the if but can't know (or doesn't check) if the condition is true and the element gets removed from the set. There is a possibility the condition is false and therefore your program won't execute the if conditions body. If you add an else and you remove an element there, too, all should be good. Or you don't use an iterator but copy the elements into an array and then use the array to get an object the list contains

Object[] cat = cats.toArray();
cats.remove((Cat) cat[0]);

or instead of an array an ArrayList

ArrayList<Cat> tempCatList = new ArrayList<>(cats);
cats.remove(catList.get(0));

Another possibility: I do not know if the validator accepts a static catToDel variable. Here you could, when creating the set, save a refernce to one of the elements and then use that static var later to remove that cat. Or you use the Iterator and just delete all set elements. That should work as well (at least it did for me ;) ) Nevertheless your solution is really good and creative. I like it.

Dmitri

Level 22 , Seversk, Russia

1 November 2020, 12:02

Thank you, I think it is If operator that the validator doesn't like.