whats the problem?

Question

import java.util.Scanner;
import java.util.ArrayList;
public class Remove{

static boolean pressed = false;

public static void press(){
pressed = true;
}
public static void notPressing(){
pressed = false;
}
}

public class Main
{
public static void main(String[] args) {

Scanner scan = new Scanner(System.in);
String x = scan.nextLine();

ArrayList<String> arr = new ArrayList<String>();

arr.add ("Jonathan");
arr.add ("Ron");
arr.add ("Levi");
arr.add ("Morlo");

Remove r = new Remove();

// r.press();

if (r.pressed == true && (x == "Jonathan" || "Ron" || "Levi" || "Morlo")){

arr.remove (x);
System.out.println (arr);

}else if (x != "Jonathan" || "Ron" || "Levi" || "Morlo"){
System.out.println ("There is no such a Participant");
}else{
System.out.println (arr);
}

}
}

Answer 1

You are missing the check to x in the or-statements.

x == "Jonathan" || "Ron"
-> x == "Jonathan" || x == "Ron"

Also your else would be wrong even with correct variable check. There it would have to be && instead of ||, because if one is equal the others are not and will match.

You make it more simple, readable and more failure Proof by using the contains method of ArrayList.

var known = arr.contains(x);
if (r.pressed == true && known){
//...
} else if (!known) {
// ...
}
else {
// ...
}

Answer 2

var ? is this java or what? a bit confused here

Answer 3

esQmo_ look:
https://www.codejava.net/java-core/the-java-language/var-keyword-in-java

Answer 4

just saw it, not really readable code

Answer 5

shouldn't be if r.pressed == true && (x == "Jonathan" || x == "Ron" || x == "Levi" || x == "Marlon"); ?

Answer 6

thanks everybody, now it works...
import java.util.Scanner;
import java.util.ArrayList;
public class Remove{

static boolean pressed = false;

public static void press(){
pressed = true;
}
public static void notPressing(){
pressed = false;
}
}

public class Main
{
public static void main(String[] args) {

Scanner scan = new Scanner(System.in);
String x = scan.nextLine();

ArrayList<String> arr = new ArrayList<String>();

arr.add ("Jonathan");
arr.add ("Ron");
arr.add ("Levi");
arr.add ("Morlo");

Remove r = new Remove();

var here = arr.contains(x);

// r.press();

if (r.pressed == true && here){

arr.remove (x);
System.out.println (arr);

}else if (!here){
System.out.println ("There is no such a Participant.");
}else if (r.pressed == false){
System.out.println (arr);
}

}
}

Answer 7

thats what Manu told me, and it works... :)
i will check right now what var does in java

Answer 8

AFAIK, var is not a keyword in java

Answer 9

you could simply do if(r.pressed && arr.contains(x)){}

Answer 10

ah that's a Java 10 thing, great I learned something today!

Answer 11

yes.. doesnt really metter tho... thanks for the help