Guessing symbols in a Sting word java

Question

Got a String like:

String str = "###############";

Got guess word, for example:

String guess = "Java"

User must guess word:

User input:

Sava

Sring should be:

String str = "#a#a###########";

all right symbols placed on their indexes

String is immutable class.

I chose Stringbuilder

 for (int i = 0; i < length ; i++) {
    if (rnd.charAt(i) == guess.charAt(i) && rnd.charAt(i) != '#'){
       sb.append(rnd.charAt(i));
        }
   }

 System.out.println(sb);

 sb.delete(0, sb.length());

Stringbuilder add right symbols not on possition 'i', but on the last indexes.

Example:

guess word: Java

user input Sala:

System.out.println(sb);

###############aa

How I can achieve needed result? And what tools should I use?

needed result:

Example:
guess word Java:

user input Sala:


System.out.println(sb);
#a#a###########

Answer 1

Work like this:

private static String word(){
    String guess = new Scanner(System.in).nextLine();
    return guess;
}

private static void guessWord(String[]arr) {
    int random = new Random().nextInt(arr.length);
    String rnd = arr[random];

    int length = 15;

    StringBuilder sb = new StringBuilder();
    String guess = "";

    int rndLength = length - rnd.length();
    int guessLength = length - guess.length();


    do {
        System.out.println("Enter a word: ");
        guess = word();

       if (sb.length() < length){
           for (int i = 0; i < length ; i++) {
               sb.append("#");
           }
       }

        for (int i = 0; i < length  && i < rnd.length() && i < guess.length();  i++) {
            if (rnd.charAt(i) == guess.charAt(i)){
                sb.setCharAt(i, rnd.charAt(i));
                sb.delete(length, sb.length());
            }
        }

        if (rnd.equals(guess)){
            System.out.println("Guess word: " + rnd);
            break;
        }else if (!rnd.equals(guess)) {
            System.out.println(sb);
        }
    }while (!rnd.equals(guess));
}