Don't get it

Frage zur Aufgabe

In der Diskussion

every time I run it, it gets the right outcome. but codegym seems to refuse that it works. Or maybe i've missed something. But I don't know what.

Gib über die Tastatur eine Zahl ein.
Wenn die Zahl positiv ist, dann verdopple sie.
Wenn die Zahl negativ ist, dann addiere 1 hinzu.
Wenn die eingegebene Zahl 0 ist, dann zeige 0 an.
Zeige das Ergebnis auf dem Bildschirm an.

Anforderungen:

Das Programm muss eine Zahl von der Tastatur einlesen.
Das Programm muss eine Zahl auf dem Bildschirm anzeigen.
Wenn die eingegebene Zahl positiv ist, verdopple sie und zeige das Ergebnis an.
Wenn die eingegebene Zahl negativ ist, erhöhe sie um 1 und zeige das Ergebnis an.
Wenn die eingegebene Zahl 0 ist, dann zeige 0 an.

package de.codegym.task.task04.task0412; /* Positive und negative Zahlen */ import java.util.Scanner; import java.io.*; public class Solution { public static void main(String[] args) throws Exception { Scanner sc = new Scanner(System.in); String eingabe= sc.nextLine(); int zahl = Integer.parseInt(eingabe); if (zahl>0){ zahl=zahl*2; System.out.println(zahl); }if (zahl <0){ zahl++; System.out.println(zahl); }if(zahl==0) { System.out.println("0"); } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

15 Mai 2020, 16:43

I see you solved the problem, if you took the original code and entered -1 the output would have been: 0 0 Which would have been incorrect. This is because if statements always process when placed one after the other. 'if-else' statements, on the other hand, will only process until the first one in line returns true. The middle if statement, at line 17, adds 1 to the value of zahl if it is less than 0, which -1 would be, so it sets its new value to 0 and outputs that. The code would then continue to line 20 and the value of zahl is 0 as the last if statement set it to that. This would return true and output 0 again. You solved it by making your statements if else statements; alternatively you could have solved it by not changing the value of 'zahl' and instead just outputting according to the requirements. Example:

if (zahl>0){
   // zahl = zahl * 2;   <--- don't change the value
   System.out.println(zahl * 2); // just output instead
}

Thomas

Level 41 , Bayreuth, Germany

13 Mai 2020, 18:36

Don't see a problem with zahl++. The only thing that comes to my mind is, that you don't output 0 as int, but as string. Maybe the validation confuses that. I'd change that (displying 0 as number or just zahl) and let it recheck. If that doesn't help reply and I post my solution

Tobias

Level 8 , Ludwigsburg, Deutschland

15 Mai 2020, 16:33

I changed the "if"'s to "else if" then it worked for some reason. maybe it's like a better "Style of Syntax" or so...

Tobias

Level 8 , Ludwigsburg, Deutschland

15 Mai 2020, 16:33

But thank you very much anyway :)