what is the error Help me

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I don't know why my code doesn't run even though I re-corrected everything. Please see my code for both of these points. I can't compile the code.

1. Dans la classe Solution, crée une classe public static Chat.
2. Implémente la méthode creerChats. Elle doit créer un ensemble (Set) de chats et lui ajouter 3 chats.
3. Dans la méthode main, supprime un chat du Set chats.
4. Implémente la méthode imprimerChats. Elle doit afficher tous les chats qui restent dans l'ensemble.
Utilise une nouvelle ligne pour chaque chat.

Impératifs :

Le programme doit afficher du texte à l'écran.
À l'intérieur de la classe Solution, il doit y avoir une classe public static Chat avec un constructeur par défaut.
La méthode creerChats() de la classe Solution doit renvoyer un Set contenant 3 chats.
La méthode imprimerChats() de la classe Solution doit afficher tous les chats dans l'ensemble. Utilise une nouvelle ligne pour chaque chat.
La méthode main() doit appeler la méthode creerChats() une fois.
La méthode main() doit appeler la méthode imprimerChats().
La méthode main() doit supprimer un chat de l'ensemble (Set) de chats.

package fr.codegym.task.task08.task0819; import java.util.HashSet; import java.util.Iterator; import java.util.Set; /* Ensemble de chats */ public class Solution { public static void main(String[] args) { Set<Chat> chats = creerChats(); Chat supprimerChat = new Chat("Chat1"); Iterator<Chat> iter = chats.iterator(); while (iter.hasNext()) { Chat chat = iter.next(); if (chat.equals(supprimerChat)) { iter.remove(); // System.out.println("Chat supprimé : " + chat); break; } } imprimerChats(chats); } public static Set<Chat> creerChats() { Set<Chat> set = new HashSet<>(); Chat chat1 = new Chat("Chat1"); Chat chat2 = new Chat("Chat2"); Chat chat3 = new Chat("Chat3"); set.add(chat1); set.add(chat2); set.add(chat3); return set; } public static void imprimerChats(Set<Chat> chats) { for (Chat chat : chats) { System.out.println(chat); } } // Classe Chat public static class Chat { private String nom; public Chat() { this.nom = "Inconnu"; } public Chat(String nom) { this.nom = nom; } public String getNom() { return nom; } public void setNom(String nom) { this.nom = nom; } @Override public String toString() { return "Nom Chat : " + nom; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null || getClass() != obj.getClass()) return false; Chat chat = (Chat) obj; return nom.equals(chat.nom); } @Override public int hashCode() { return nom.hashCode(); } } }

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Thomas

niveau Bayreuth, Bayreuth, Germany

21 juillet, 15:07

solution

Let me first say that I don't know Codegyms test cases but imho validation will create an own set using the no-args constructor (as it does not know what fields you created if any). Then it will test your main mehtods code using your set and the sets it created itself to validate if all is working correctly. And let me tell you... it does not. Using only the default constructor your code does not delete any entry and will create only a set with one entry. If using the constructor taking a String with any value (except Chat1) your code will delete nothing. So in the end I guess implementing the equals method makes validation go haywire. As said, I don't know what CG tests. So I'd try to keep things more abstract. The minimal possible (static) class is

public static class Chat {}

Using this class add three elements to your set.

for (int i = 0; i < 3; i++) {
   set.add(new Chat());
}

Approach 1: Now just think about a possibility to just get one element from the set using the Iterator object

while (it.hasNext()) {

while loops as long as the condition is true. But isn't there another keyword that only executes a code block just once for a true condition? Approach 2: Eventually, I don't know if CG likes it, you just can rely on the set being initialized with three elements and just call

it.next();
it.remove();

Approach 3: Or, if you insist on a while loop, just have a counter variable. Increment it inside the loop and if it == 0 or 1 or whatever, remove an element. Approach 4: use while and break ... and more

ABDOULRAHMAN ADEN DAHER

niveau DJBOUTI, DJBOUTI, Djibouti

22 juillet, 06:42

Thank you very much Thomas, I delete all the contents of the Chat class and leave empty as you suggested the code works perfectly. Basically a public static Chat class with a default constructor. is an empty class while I put other information by default sometimes the CodeGyme does not give us more details on the exercise is it is a very good thing that we use our brain

Thomas

niveau Bayreuth, Bayreuth, Germany

22 juillet, 06:59

My pleasure... and happy learning.