ArrayIndexOutOfBoundsException in Hangman game

Question

I'm trying to create a Hangman game but I don't know how to properly initialize the wordDisplay array, it gives an error this array is supposed to print out underscores for letters of the word to guess and then the underscores get replaced by letters that were guessed by the player

public class Hangman
{
    static Scanner userInput = new Scanner(System.in);

    public static void main(String args[])
    {
        String strword = "wordo";
        char[] theWord = strword.toCharArray();
        int k = strword.length();
        int c;

        char[] wordDisplay;

        for(c=0;c<=k;c++)
        {
            wordDisplay[c] = '_';
        }

        int hang = 0;
        int i;

        while(hang<k+10)
        {

            System.out.println("type a letter");

            for(i=0;i<5;i++)
            {
                System.out.print( wordDisplay[i] );
            }
            char userLetter = userInput.next().charAt(0);
            for(i=0;i<=k;i++)
            {
                if(userLetter==theWord[i])
                {
                    System.out.println("a letter guessed");
                    wordDisplay[i] = theWord[i];
                }
                else
                {
                    hang++;
                }
            }


        }   
        System.out.println("you hang");
    }

}

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5 at test2.Hangman.main(Hangman.java:19) — coldman1, Dec 13 '16 at 13:31
You only _declared_ `wordDisplay` but never _initialized_ it so its value will always be `null`. Change `char[] wordDisplay` to `char[] wordDisplay = new char[k]` then it should work. Also in your for-loop you need to change `<=` to `<` or you'd get an IndexOutOfBoundsException. — mammago, Dec 13 '16 at 13:35
is this really Java? This code should not compile at all - the compiler is smart enough to complain about the uninitialized variable. — user85421, Dec 13 '16 at 14:39

xenteros · Answer 1 · 2016-12-13T13:34:37.653

2

Instead of

    char[] wordDisplay;

    for(c=0;c<=k;c++)
    {
        wordDisplay[c] = '_';
    }

write:

    char[] wordDisplay = new char[k+1];
    for(c=0;c<=k;c++) {
        wordDisplay[c] = '_';
    }

or

    char[] wordDisplay = new char[k];
    for(c=0;c<k;c++) {
        wordDisplay[c] = '_';
    }

Each object in Java must be initialized.

edited Dec 13 '16 at 13:34

answered Dec 13 '16 at 13:33

xenteros

15,586
12
56
91

Eh I did that and after I type in one letter, it gives the same error – coldman1 Dec 13 '16 at 13:39
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5 at test2.Hangman.main(Hangman.java:35) – coldman1 Dec 13 '16 at 13:47
nevermind I fixed it – coldman1 Dec 13 '16 at 13:49

Kiogara · Answer 2 · 2016-12-13T13:36:47.233

1

Initialize your array with the length you have

char[] wordDisplay = new char[k]

and change your for to:

for(c=0;c<k;c++)
  {
    wordDisplay[c] = '_';
  }

Keep in mind that your first index is 0

edited Dec 13 '16 at 13:36

answered Dec 13 '16 at 13:33

Kiogara

617
1
6
15

@coldcash consider accepting/ upvoting/ both if it answered your question so others are aware. – Luke Briggs Dec 13 '16 at 13:38

score -1 · Answer 3 · answered Dec 13 '16 at 13:34

-1

You have not only to declare but to initialize the array. Since an array has a fixed size you should initialize it with it's size. That on the other hand is the length off the input string. So e.g:

char[] wordDisplay = new char[k];

answered Dec 13 '16 at 13:34

Robin Koch

716
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12

ArrayIndexOutOfBoundsException in Hangman game

3 Answers3