Thread: Hangman Program Java: Comparing the User's Guess with Another String Letter by Letter

I'm making a Hangman program to test my knowledge of GUI's. However my program is not checking letters correctly. This is my code for a Field Listener that checks the user's input with the word. I'm not posting all of the code because it is not all relevant to the issue and is working fine. The field listener is called after the user inputs text and presses the enter key. The object word.letters is a random String from a dictionary file. My problem has two parts: if the user inputs a correct letter the for loop never runs and the letter is instead counted as wrong in the else statement. My second problem is that if the user inputs the correct word it doesn't say it is correct instead it says it is an invalid guess. I hope this is enough.

The listener does handle invalid guesses correctly and wrong letters (but counts right letters as wrong).

class fieldListener implements ActionListener {
     @Override
     public void actionPerformed(ActionEvent ae) {
         if (guesses > 0) {
            String guess = field.getText(); //gets the text from field
            if (guess.length() == 1 && gc.contains(guess) == false && Arrays.asList(word.letters.toCharArray()).contains(guess)) { //if the guess is one letter long and is not found in the ArrayList gc containing guessed letters and word.letters contains the letter
                for (int i = 0; i < word.letters.length(); i++) { //for every letter in word.letters
                    String str = ""; //this represents a JLabel that uses underscores for every letter of word.letters
                    if (guess.equals(word.letters.charAt(i) + "")) { //if one letter is equal
                        str += guess + " "; //change the underscore to the letter
                        word.flags[i] = true; //set that letters flag to true meaning it has been found
                        area.setText("You guessed a correct letter."); //print the result
                        gc.addElement(guess); //add the letter to the found list
                        list = new JList(gc); //refresh the JList
                        field.setText(""); //empty the guess field
                    }
                    else if (word.flags[i] == true){ //otherwise if that letters flag is true
                        str += word.letters.charAt(i) + " "; //add the letter to the label
                    }
                    else {
                        str += "_ "; //otherwise add an underscore representing no found letter
                    }
                    t.setText(str); //set the label to the value of str
                }
            }
            else if (guess.equals(word.letters)) {
                win(); //if the guess equals the random word execute the win function
                list = new JList(gc); //update the JList
                field.setText(""); //empty field
            }
            else if (guess.length() > 1 && (guess.length() < word.letters.length() || guess.length() > word.letters.length())) {
                area.setText("Only guess letters or the entire word."); //if the guess is not one letter or the length of the word tell the user he made an invalid guess
                field.setText(""); //empty
            }
            else if (gc.contains(guess)) { //self explanatory
                area.setText("You already guessed that.");
                field.setText("");
            }
            else { //if its a wrong letter or wrong word
                guesses--; //decrement the guesses
                gc.addElement(guess.toLowerCase()); //add the word/letter to the scroller 
                area.setText("Wrong, guess another letter or the word."); //result
                list = new JList(gc); //update list
                f.repaint(); //repaint the frame to add the next body part
                field.setText("");
            }
 
            if (!Arrays.asList(word.flags).contains(false)) {
                win(); //if there are no more false flags left execute win
            }
         }
         if (guesses == 0) {
             lose(); //if guesses = 0 execute lose
         }
     }
}

Hi theonlydvr, welcome to the forums!

if the user inputs a correct letter the for loop never runs

Arrays.asList(word.letters.toCharArray()).contains(guess)

Assuming that word.letters is a String, it seems to me that this expression will never be true. toCharArray() returns an array of char and asList() will produce some sort of List whose members are of the Character type. This list will never contain guess because guess is declared as a String not a Character or char.

if the user inputs the correct word it doesn't say it is correct

I have no idea why "guess.equals(word.letters)" doesn't evaluate to true. Presumably it is because of how you declared words.letters and what values you assigned to it in the code you haven't posted. You could print the two strings to System.out at some point to check what's going on.

@Override
public void actionPerformed(ActionEvent ae) {
    if (guesses > 0) {
        String guess = field.getText(); //gets the text from field
        System.out.println("At field listener actionPerformed() guesses=" + guesses);
        System.out.println("guess=|" + guess + "|");
        System.out.println("word.letters=|" + word.letters + "|");
 
        // etc

(The reason for the | symbols is because you want to be able to see any whitespace that might be frustrating the string comparison.)

I fixed the program!!! My problem was that I wasn't initializing word.flags. Thank you so much pb!

You're welcome. I'm glad you got it sorted out.

Did you System.out.println(words.flags)? That would be my response to the null pointer exception.

---

Ignore this if you are happy with the program as it is...

I would consider making the Word class a bit less "passive".

    /**
     * A class representing a word letters of which have been guessed.
     */
class Word { 
    private String letters;
    private boolean[] flags;
 
    public Word(String letters) {
        this.letters = letters;
        flags = new boolean[letters.length]; // !
    }    
 
        /**
         * Updates the flags for a given guess.
         *
         * Returns 0 if the given character wasn't present, -1 if it had already been
         * guessed and 1 if the flags array was changed.
         */
    public int updateFlags(char ch) {
        // ...
    }
 
    // and maybe getter methods
}

That's just a sketch of course, but it seems a good place to put the code that does the guess checking. In general gui code (with its listeners etc) is quite complex enough without involving other things.

And notice how flags can't help but be initialised correctly when it is placed inside a constructor.