Using a basic java code please. thank you! Programming assignment Caesar Shift 5

Question

Using a basic java code please. thank you!

Programming assignment Caesar Shift 5 points. You are going to build a program that encodes messages using a simple Caesar Shift algorithm. The user will type in a message to be encoded, and your program will output an encrypted version of the users input. What is a Caesar Shift you might ask? Basically we are shifting the letters such that: original letter XYZABCDEFGHIJKLMNIPQURSUVW Encoded letter ABCDEFGHIJKLMNOPQRSTUVWXYZ IE the letter 'C' in the original message is printed as the letter 'F' in the encoded message (Three characters over) In order to do this, you need to understand a bit of how letters are encoded. If a Char represents a single letter, you can get a numerical value for that letter by saying char original = 'H'; int letterValue = original; For the letter 'H' the numeric value is 72. The values for A thru Z are 65 thru 90. Here is some psudo code. Input the user's string - convert it to upper case - examine each character in the string one at a time. If the character is a letter (ie 65 to 90) subtract three from the value. If the resulting value is less than 65, add 26 to it convert the value to a char, and add it to the encoded string Print the resultant encoded string you created.

Explanation / Answer

//include package

package com.sanfoundry.setandstring;

import java.util.Scanner;

public class Caesar_shift

{

    public static final String ALPHABET = "abcdefghijklmnopqrstuvwxyz";

    public static String encrypt(String plainText, int shiftKey)

    {

// check lower case alphabet

        plainText = plainText.toLowerCase();

        String cipherText = "";

        for (int i = 0; i < plainText.length(); i++)

        {

            int charPosition = ALPHABET.indexOf(plainText.charAt(i));

            int keyVal = (shiftKey + charPosition) % 26;

            char replaceVal = ALPHABET.charAt(keyVal);

            cipherText += replaceVal;

        }

        return cipherText;

    }

// decrpt funcion

    public static String decrypt(String cipherText, int shiftKey)

    {

        cipherText = cipherText.toLowerCase();

        String plainText = "";

        for (int i = 0; i < cipherText.length(); i++)

        {

            int charPosition = ALPHABET.indexOf(cipherText.charAt(i));

            int keyVal = (charPosition - shiftKey) % 26;

            if (keyVal < 0)

            {

                keyVal = ALPHABET.length() + keyVal;

            }

            char replaceVal = ALPHABET.charAt(keyVal);

            plainText += replaceVal;

        }

        return plainText;

    }

//main class

public static void main(String[] args)

    {

        Scanner sc = new Scanner(System.in);

        System.out.println("Enter the String for Encryption: ");

        String message = new String();

        message = sc.next();

        System.out.println(encrypt(message, 3));

        System.out.println(decrypt(encrypt(message, 3), 3));

        sc.close();

    }

}

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