HangmanLogic.java

public class HangmanLogic {

    private String word;
    private String guessedLetters;
    private int numberOfFaults;

    public HangmanLogic(String word) {
        this.word = word.toUpperCase();
        this.guessedLetters = "";
        this.numberOfFaults = 0;
    }

    public int numberOfFaults() {
        return this.numberOfFaults;
    }

    public String guessedLetters() {
        return this.guessedLetters;
    }

    public int losingFaultAmount() {
        return 12;
    }

    public void guessLetter(String letter) {
        if (!this.guessedLetters.contains(letter)) {
            if (!this.word.contains(letter)) {
                this.numberOfFaults++;
            }
            this.guessedLetters += letter;
        }
        // program here the functionality for making a guess

        // if the letter has already been guessed, nothing happens

        // it the word does not contains the guessed letter, number of faults increase
        // the letter is added among the already guessed letters
    }

    public String hiddenWord() {
        // program here the functionality for building the hidden word

        // create the hidden word by interating through this.word letter by letter
        // if the letter in turn is within the guessed words, put it in to the hidden word
        // if the letter is not among guessed, replace it with _ in the hidden word 

        // return the hidden word at the end

        int i = 0;
        String hiddenWordString = "";
        while (i < this.word.length()) {
            char c = this.word.charAt(i);
            String wordLetterString = "" + c;
            if(this.guessedLetters.contains(wordLetterString)) {
                hiddenWordString += c;
            } else {
                hiddenWordString += "_";
            }
            
            i++;
//            if (this.word.indexOf(c) >= 0) {
//                hiddenWordString +=  "" + c; //this.guessedLetters.charAt(i);
//            } else {
//                hiddenWordString += "_";
//            }
        }
        
        
        return hiddenWordString;
    }
}