Question

I have researched this topic for a while, but without much success. I did find the StringBuilder and it works wonders, but that’s as far as I got. Here is how I got my hangman program to work like it should:

  if(strGuess.equalsIgnoreCase("t")){
        mainword.replace(0,1,"T");
        gletters.append('T');      
    }
        else if(strGuess.equalsIgnoreCase("e")){
        mainword.replace(1,2,"E");
        gletters.append('E');       
    }
        else if(strGuess.equalsIgnoreCase("c")){
        mainword.replace(2,3,"C");
        gletters.append('C');         
    }
        else if(strGuess.equalsIgnoreCase("h")){
        mainword.replace(3,4,"H");
        gletters.append('H');      
    }
        else if(strGuess.equalsIgnoreCase("n")){
        mainword.replace(4,5,"N");
        gletters.append('N');      
    }
        else if(strGuess.equalsIgnoreCase("o")){
        mainword.replace(5,6,"O");
        mainword.replace(7,8,"O");
        gletters.append('O');       
    }
        else if(strGuess.equalsIgnoreCase("l")){
        mainword.replace(6,7,"L");
        gletters.append('L');       
    }
         else if(strGuess.equalsIgnoreCase("g")){
        mainword.replace(8,9,"G");
        gletters.append('G');      
    }
        else if(strGuess.equalsIgnoreCase("y")){
        mainword.replace(9,10,"Y");
        gletters.append('Y'); 
    }
        else{
        JOptionPane.showMessageDialog(null, "Sorry, that wasn't in the word!");
        errors++;
        gletters.append(strGuess.toUpperCase());
    }
        SetMain = mainword.toString();
        GuessedLetters = gletters.toString();
        WordLabel.setText(SetMain);
        GuessedLabel.setText(GuessedLetters);
        GuessText.setText(null);
        GuessText.requestFocusInWindow();

However, I can’t do this for EVERY letter for EVERY word, so is there a simple and efficient way to do this? What I want is to have a loop of some sort so that I would only have to use it once for whatever word. So the word could be technology (like it is above) or apple or pickles or christmas or hello or whatever.

I have tried using a for loop, and I feel the answer lies in that. And if someone could explain the charAt() method and how/where to use it, that’d be good. The closest I got to being more efficient is:

for(i = 0; i < GuessWord.length(); i++) { 
    if (GuessWord.charAt(i) == guess2) { 
        mainword.replace(i,i,strGuess.toUpperCase()); 
    }

So if you could use that as a basis and go off of it, like fix it? Or tell me something I haven’t thought of.

Answer 1

It’s a good question. There’s clearly repeated code, so how do you replace all that with something reusable. Actually, you can dispense with all of your code.

That whole code block can be replaced by just one line (that works for every word)!

String word = "TECHNOLOGY"; // This is the word the user must guess
mainword = word.replaceAll("[^" + gletters + "]", "_");

This uses replaceAll() with a regex that means “any letter not already guessed” and replaces it with a underscore character "_". Note that Strings are immutable, and the replaceAll() method returns the modified String – it doesn’t modify the String called on.

Here’s some test code to show it in action:

public static void main(String[] args) {
    String word = "TECHNOLOGY"; // what the user must guess
    StringBuilder gletters = new StringBuilder("GOTCHA"); // letters guessed
    String mainword = word.replaceAll("[^" + gletters + "]", "_");
    System.out.println(mainword);
}

Output:

T_CH_O_OG_