getting IllegalArgumentsException and confused

[pastel hamlet]

So im using HyperSkill and im on the last stage of the rock paper scissors game, here is a link to the stage and directions.
https://hyperskill.org/projects/314/stages/1768/implement
Anyway im confused on why i'm receiving an IllegalArgumentsException on my copyOfRange method in my determineWinner method. I know that it takes 3 arguments the Original Array the star and finish, as far as i can tell all my arguments are in range. Any help with helping me understand this and nudge me in the right direction would be greatly appreciated 🙂
here is my gist of what i have so far.
https://gist.github.com/AviTheBrown/848ee7b0ae63b788473c80818f3404e0

[dense smelt]

<@&987246399047479336> please have a look, thanks.

[dense smelt]

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[drifting cradle]

Throws:
ArrayIndexOutOfBoundsException – if from < 0 or from > original.length
IllegalArgumentException – if from > to
NullPointerException – if original is null

So in this case, your from > to

Which probably means your weaponIndex is not actually getting read properly

You should print out the value of weaponIndex and see what it is @pastel hamlet

[pastel hamlet]

Thank you let me check that out. 🙂

[pastel hamlet]

it comes back as -1, so now i need to figure out how to actually get the index that corresponds to the weapon in the Array?

[drifting cradle]

well now

[pastel hamlet]

but why -1? is that default for no null?

but not included?

[drifting cradle]

it means it couldn't find the index

[pastel hamlet]

ok

[drifting cradle]

so now try printing the contents of the array

[pastel hamlet]

lol i see where this is going.

[drifting cradle]

the GameWeaponsArr

yeah it is probably empty or something goofy

[pastel hamlet]

but i thought this would fill the array

    private String setWeapons(String gameWeapons) {
        GameWeaponsArr = gameWeapons.split(",");
        this.gameWeapons = Arrays.toString(GameWeaponsArr);
        // encase the user accidentally presses the space bar.
        return gameWeapons.replace(" ", "");
    }

[dense smelt]

Detected code, here are some useful tools:

[pastel hamlet]

@drifting cradle

[drifting cradle]

it does

what are you inputting

[pastel hamlet]

but the determineWinner is called after the method to fill the array is called. therefore shouldnt it be fille.

filled*

[drifting cradle]

Can you share you console

of what you are inputting in

[pastel hamlet]

ok.

@drifting cradle

[drifting cradle]

You are printing out the hashcode of the array. Do

System.out.println(Arrays.toString(GameWeaponsArr));

You'll still get the same error, but now at least you can see the contents of the array

let me know once you did that 😄

[pastel hamlet]

yeah i cant believe that i forgot to parse it to string

yeah its empty 😢

[drifting cradle]

Yeah so

You are passing into setWeapons() an empty string

try this

[pastel hamlet]

hmm check this out.

[drifting cradle]

Ope sorry my internet went down😂

Once it says Hello, your name

Enter this:

rock,paper,scissors

[pastel hamlet]

so i have the deafault wrong. its not copying in the GameWeaponArr??

@drifting cradle

look at this method

 private String getComputerChoice() {
        String theWeapon = "";

        if (Objects.equals(gameWeapons, "rock,paper,scissors")){
            Random random = new Random();
            int randomNumForDefault = random.nextInt(3);
            switch (randomNumForDefault) {
                case 0 ->  theWeapon = "rock";
                case 1 ->  theWeapon = "paper";
                case 2 ->  theWeapon = "scissors";
            }
        } else {
            Random rand = new Random();
            int randomIndex = rand.nextInt(GameWeaponsArr.length);
            theWeapon = GameWeaponsArr[randomIndex];
        }
        return theWeapon;
    }

if the user just presses enter the default weapons should be rock paper scissors. but i think im doing something wrong here.

[drifting cradle]

yeah

so

If the user enters nothing, your setWeapons() should default it to the appropriate weapons

[pastel hamlet]

@drifting cradle actually this is the wrong code. this is what i wanted to show you

    private String setWeapons(String gameWeapons) {

        GameWeaponsArr = gameWeapons.split(",");
        this.gameWeapons = Arrays.toString(GameWeaponsArr);
        // encase the user accidentally presses the space bar.
        return gameWeapons.replace(" ", "");
    }

[drifting cradle]

Yeah exactly

you need to do a check on gameWeapons

[pastel hamlet]

yes!

[drifting cradle]

if it is empty, populate it with rock paper and scissors

[pastel hamlet]

this is what is came up with.

    private String setWeapons(String gameWeapons) {
        if (gameWeapons.equals("")) {
            gameWeapons = "rock,paper,scissors";
        }
        GameWeaponsArr = gameWeapons.split(",");
        this.gameWeapons = Arrays.toString(GameWeaponsArr);
        // encase the user accidentally presses the space bar.
        return gameWeapons.replace(" ", "");
    }

it works and fills it with the default.
but there is still the exception.

[drifting cradle]

are you still printing out weaponIndex?

[pastel hamlet]

no let me see.

[drifting cradle]

I'm sure it's still -1

because you are not setting GameWeaponsArr

you should have an if/else in that statement

if the user input is empty:
    set gameWeapons to rock/paper/scissors
    set array to rock,paper,scissors
else:
    split the input
    set gameWeapons to input
    set array to input

[pastel hamlet]

not its not. it actually prints the right index

[drifting cradle]

Well your GameWeaponsArr is still empty

you never put anything in it

[pastel hamlet]

but isnt the elements displayed in the array [rock, paper, scissors]?

[drifting cradle]

ah wait sorry

didn't see you split it

okay yeah you are all good then with filling it

[pastel hamlet]

thank but for some reson it still gives that same eception

[drifting cradle]

something just came up irl, I would love to continue helping, I can continue if you give me maybe 15 minutes

[pastel hamlet]

ok thanks 🙂

[drifting cradle]

I can tell you right now though

your logic behind copying what is after the array and before is incorrect

since you never take into account if it's the last index or not of the array

but give me 15

[pastel hamlet]

ok

[drifting cradle]

Okay hey sorry I'm back you still here?

[pastel hamlet]

@drifting cradle im here

[drifting cradle]

so

[pastel hamlet]

i see what you mean im not checking where the selectedWeapon is located in the arr.

my brain didnt even think about that.

[drifting cradle]

well I think it's actually weirdly enough fine

        String[] firstArray = Arrays.copyOfRange(GameWeaponsArr, 0, weaponIndex);
        // the second Array are all the elements that are listed after the selectedWeapon
        String[] secondArray = Arrays.copyOfRange(GameWeaponsArr, weaponIndex + 1, GameWeaponsArr.length);

you shouldn't subtract 1 from the length

[pastel hamlet]

oh ok. i thought that lenght counts all the elements but it starts from 1 not 0 as the index does. thats why i thought to subtract 1

[drifting cradle]

well it's exlusive

so the to can lie outside the array

so in this case, you were picking the very last index

but it wasn't being used since it's not inclusive

[pastel hamlet]

oh ok i see.

this is good. but if you see the rules from the project its very confusing and i dont know how to loop the elements to get the results they want.

if users input an empty line, start the game with default options: rock, paper, and scissors.

Once the game options are defined, output Okay, let's start.


Regardless of the chosen options, your program, obviously, should identify which option beats which. You can use the following algorithm. First, every option produces a draw when opposed to itself. Secondly, every option beats half of the other options and is defeated by another half. How to determine which options are stronger or weaker? Take the list of options provided by the user and pick the option that you want to know the relationships of. Take all other options from the user's list. Add them to the list of options that precede the chosen option. Now, you have another list of options that don't include the user's option with a different order of elements inside. First are the options that follow the chosen one in the original list; then, there are the ones that precede it. So, in this "new" list, the first half of the options defeat the "chosen" option, and the second half is beaten by it.

For example, the user's list of options is rock,paper,scissors,lizard,spock. You want to know what options are weaker than lizard. By looking at the list spock,rock,paper,scissors you realize that spock and rock beat lizard. Paper and scissors are defeated by it. For spock, it'll be almost the same, but it'll get beaten by rock and paper, and prevail over scissors and lizard.

[drifting cradle]

so you really already have everything

[pastel hamlet]

i see where im messing up.

[drifting cradle]

you really already have everything

it should work with the fix I posted above

[pastel hamlet]

in this line

For example, the user's list of options is rock,paper,scissors,lizard,spock. You want to know what options are weaker than lizard. By looking at the list spock,rock,paper,scissors you realize that spock and rock beat lizard.

so spock is the first element in the new Arr. so does this create an array that will follow that patter.

        String[] firstArray = Arrays.copyOfRange(GameWeaponsArr, 0, weaponIndex);
        String[] secondArray = Arrays.copyOfRange(GameWeaponsArr, weaponIndex + 1, GameWeaponsArr.length);


        List<String> newWeaponList = new ArrayList<>(Arrays.asList(secondArray));
        newWeaponList.addAll(Arrays.asList(firstArray));
        String[] finalArray = newWeaponList.toArray(new String[0]);

[drifting cradle]

well

right

so you make an arraylist with the secondarray

then you add the first array content into it

then split the array in half

the first part of it wins

the second part loses

[pastel hamlet]

but what if the userWeapon is the last element like you said???

thank you again for helping me. i know its late. if i cant get this ill just move on to another project 😢

[drifting cradle]

ah sorry, my mind isn't in it right now sorry 😆

[pastel hamlet]

lol

thanks for the help. i will work forward 🙂

@drifting cradle

[drifting cradle]

okay I am back and concentrated 😆

you have one more off by one erorr

List<String> seconsHalfOfList = new ArrayList<>(newWeaponList.subList((newWeaponList.size() / 2), newWeaponList.size()));

@pastel hamlet then i think it works perfectly

[pastel hamlet]

@ you drink coffe ? lol

[drifting cradle]

😆 maybe..

so I think if you try that out, it should work with just rock,paper,scissors

[pastel hamlet]

ok let me see

@drifting cradle yessss it does 🙂 (with rock paper scissors)

lets see with the others.

[drifting cradle]

now to test it with the others 💃

I think it will work

dang you had a lot of off by 1 errors

you pretty much had the logic on point

[pastel hamlet]

yesss passed 2 test 🙂 but ...

it doesnt handle the invalid input right. my if else is off i think.

[drifting cradle]

That's because you are validating input in the wrong place

It should be the very first party

statement in the method*

Just add a check before you do anything fancy with lists

[pastel hamlet]

yeah your right. let me implement.

ok there is a few other things i need to do with the code before hand to check that.

@drifting cradle i did this and it checks the invalid correctly.

List<String> gameWeaponList1 = new ArrayList<>(Arrays.asList(GameWeaponsArr));

        if (userWeapon.equals("!rating")) {
            System.out.printf("Your rating: %d\n", getRating());
        } else if (userWeapon.equals("!exit")) {
            endGame();
        } else if (!gameWeaponList1.contains(userWeapon)){
            System.out.println("Invalid input");
        } else {
        // initializes the variable to the index number of the userW

[drifting cradle]

I dunno what the instructions state to do if they enter invalid data

but you could also do something like this in determineWinner

        if(!Arrays.asList(GameWeaponsArr).contains(userWeapon)){
            System.out.println("bad input");
            return;
        }

[pastel hamlet]

@drifting cradle i got it to test 7 and it failed because its reading the file wrong.

no i got the Invalid to work 🙂

[drifting cradle]

what is the file suppose to have?

ah okay awesome

[pastel hamlet]

the file

should be a .txt file with the names
Tim 350
Jane 350
Alex 350
Bob 350

i check it with is this.

   private int readContentOfFile(File file) {
        Scanner scanner1;
        try {
            scanner1 = new Scanner(file);
            while (scanner1.hasNext()) {
                String[] userData = scanner1.nextLine().split(" ");
                if (userName.equals(userData[0])) {
                    rating = Integer.parseInt(userData[1]);
                }
            }
        } catch (IOException e) {
            System.out.printf("Unable to execute %s", file.getPath());
        }
        return rating;
    }

  static File file = new File("../rating.txt");

from my Main class

ok i fixed

[drifting cradle]

awesome 💃

[pastel hamlet]

let me try one more thing then its bed time lol

[drifting cradle]

still failing a test?

[pastel hamlet]

yeah but i dont think this is a "me" thing is a bug i think.

in the project comments section they say there is a bug in that there should be a user name Bob that has a score of 350 as a starting point. so i put Bob in the file with a score of 350 but it still fails. then i take Bob out and assign him the rating/score of 350 and it still fails.

waittt hold on lol.

i didnt increase rating by 100 when they win 😅

now the last test. lol

[drifting cradle]

🥳 almost done!

[pastel hamlet]

passeddddd alll :)))))) thank you click

wish i could give you a hug!! lol

[drifting cradle]

hell yeah! Grats 🕺

[pastel hamlet]

thank so much!

[drifting cradle]

of course

[pastel hamlet]

how can i add you as friend in case in the future i need your input again??

[drifting cradle]

I'm afraid I can't do that. Part of the discord rules here :(. But you are always welcomed to continue making questions here

I or someone else will always take a look

[pastel hamlet]

ok 🙂

[pastel hamlet]

/help-thread close