public static void caesar_shift(String s) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i), xChar = ch;
            if (ch >= 65 && ch <= 90) {
                xChar = (char) (ch == 90 ? 65 : ch + 1);
            } else if (ch >= 97 && ch <= 122) {
                xChar = (char) (ch == 122 ? 97 : ch + 1);
            }

            sb.append(xChar);
        }

        System.out.println(sb.toString());
    }