Rot13.java

package id.indrasudirman.bahanujicoba;

/**
 * Created by Jabrikos on 3/16/2018.
 */

public class Rot13 {

    public static String rot13 (String value) {

        char[] values = value.toCharArray();
        for (int i = 0; i < values.length; i++) {
            char letter = values[i];

            if (letter >= 'a' && letter <= 'z') {
                // Rotate lowercase letters.

                if (letter > 'm') {
                    letter -= 13;
                } else {
                    letter += 13;
                }
            } else if (letter >= 'A' && letter <= 'Z') {
                // Rotate uppercase letters.

                if (letter > 'M') {
                    letter -= 13;
                } else {
                    letter += 13;
                }
            }
            values[i] = letter;
        }
        // Convert array to a new String.
        return new String(values);
    }

}