This project involves writing a program that encodes and decodes messages. The program should prompt the user to select whether a message is to be encoded or decoded, and then prompts the user to enter the message. A blank space is used to separate each word in the message, and a period (.) is used to denote the end of a sentence. Separate methods must be used to encode and decode the input message. The coding scheme is very simple: the code

See explaination

Explanation:

import java. util. Scanner;

public class EncodeDecodeMessage {

public static String encode (String str) {

String result = "";

char ch;

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

ch = str. charAt (i);

if (Character. isLowerCase (ch)) {

result + = (char) ('a' + (25-ch+'a'));

} else if (Character. isUpperCase (ch)) {

result + = (char) ('A' + (25-ch+'A'));

} else {

result + = ch;

}

}

return result;

}

public static String decode (String str) {

return encode (str); / / since the scheme is same, we can use encode for decode

}

public static void main (String[] args) {

Scanner in = new Scanner (System. in);

System. out. print ("1. Encode, 2. Decode. Enter your choice: ");

int choice = in. nextInt ();

in. nextLine ();

if (choice = = 1) {

System. out. print ("Enter sentence to encode: ");

String line = in. nextLine ();

System. out. println ("Encoded string is: " + encode (line));

} else if (choice = = 2) {

System. out. print ("Enter sentence to decode: ");

String line = in. nextLine ();

System. out. println ("Decoded string is: " + decode (line));

}

}

}