How to keep the desired letter and hide the other characters with “*”? Is there a simpler and efficient way?

Question

I want to keep the desired letter that the user inputs using the scanner and hide all the other characters with a \"*\", how would I do that with a for loop or substring? I

Answer 1

Try this updated version:

String letters = "";
for (int i = 0; i < 5; i++) {
    letters += keyboard.next().charAt(0) + ", ";
}

String r = "";
boolean found = false;
for (int y = 0; y < mysteryphrase.length(); y++) {
    char n = mysteryphrase.charAt(y);
    if (letters.indexOf(n) > -1) {
        r += n;
        found = true;
    } else {
        r += "*";
    }
}
if (!found) {
    System.out.println("Letters " + letters + " not in the word");
} else {
    System.out.println(r);
}

Output for input a b c d e and mysteryphrase = "acknowledgement":

ac*****ed*e*e**

Output for input q b z r s and mysteryphrase = "acknowledgement":

Letters q,b,z,r,s not in the word

Or, if you have to do this task separately for each letter (not for all five ones together), you can extract a single method and call it 5 times:

for (int i = 0; i < 5; i++) {
    char letter = keyboard.next().charAt(0);
    String r = "";
    boolean found = false;
    for (int j = 0, n = mysteryphrase.length(); j < n; j++) {
        char c = mysteryphrase.charAt(0);
        if (c == letter) {
            r += c;
            found = true;
        } else {
            r += '*';
        }
    }
    if (!found) {
        System.out.println("Letter " + letter + " not in the word");
    } else {
        System.out.println(r);
    }
}

Output:

Letter b not in the word
******l*****
a***********
*c**********
**k*********