ROT-13 function in java?

Question

Is there already a rot13() and unrot13() implementation as part of one of the standard Java libraries? Or do I have to write it myself and \"reinv

Answer 1

Here is my solution to shift chars in a string.

public static void main(String[] args) {
    String input = "melike";
    int shiftCount = 13;
    char[] encryptedChars = encryptedChars(shiftCount);
    System.out.println(new String(encryptedChars));
    char[] decryptedChars = decryptedChars(shiftCount);
    System.out.println(new String(decryptedChars));
    String encrypted = encrypt(input, shiftCount);
    System.out.println(encrypted);
    String decrypted = decrypt(encrypted, shiftCount);
    System.out.println(decrypted);
    System.out.println(input.equals(decrypted));
}

private static String decrypt(String input, int shiftCount) {
    char[] decryptedChars = decryptedChars(shiftCount);
    char[] chars = input.toCharArray();
    char[] newChars = new char[chars.length];
    for (int i = 0; i < chars.length; i++) {
        int diff = chars[i] - 'a';
        newChars[i] = decryptedChars[diff];
    }
    return new String(newChars);
}

private static String encrypt(String input, int shiftCount) {
    char[] encryptedChars = encryptedChars(shiftCount);
    char[] chars = input.toCharArray();
    char[] newChars = new char[chars.length];
    for (int i = 0; i < chars.length; i++) {
        int diff = chars[i] - 'a';
        newChars[i] = encryptedChars[diff];
    }
    return new String(newChars);
}

private static char[] encryptedChars(int shiftCount) {
    char[] newChars = new char[26];
    for (int i = 0; i < 26; i++) {
        newChars[i] = (char) ('a' + (i + shiftCount) % 26);
    }
    return newChars;
}

private static char[] decryptedChars(int shiftCount) {
    char[] newChars = new char[26];
    for (int i = 0; i < 26; i++) {
        newChars[i] = (char) ('a' + (i - shiftCount + 26) % 26);
    }
    return newChars;
}