// Marty Stepp, CSE 142, Autumn 2008
// This program reads a message and a secret key from the user and
// encrypts the message using a Caesar cipher, shifting each letter.

import java.util.*;

public class SecretMessage {
    public static void main(String[] args) {
        Scanner console = new Scanner(System.in);
        
        // read message and 'key' to shift by
        System.out.print("Your secret message: ");
        String message = console.nextLine();
        message = message.toLowerCase();
        
        System.out.print("Your secret key: ");
        int key = console.nextInt();
        
        // encode message with Caesar cipher
        encode(message, key);
    }
    
    // This method encodes the given text string using a Caesar
    // cipher, shifting each letter by the given number of places.
    public static void encode(String text, int shift) {
        System.out.print("The encoded message: ");
        for (int i = 0; i < text.length(); i++) {
            char letter = text.charAt(i);

            // shift only letters (leave other characters alone)
            if (letter >= 'a' && letter <= 'z') {
                letter = (char) (letter + shift);

                // may need to wrap around
                if (letter > 'z') {
                    letter = (char) (letter - 26);
                } else if (letter < 'a') {
                    letter = (char) (letter + 26);
                }
            }
            System.out.print(letter);
        }
        System.out.println();
    }
}