Question

Write a program that prompts a user, using Scanner, for 2 secret messages. Each message has its own set of rules you need to use to decode it. You will use String methods to change the messages you receive from the user.

*Note: Ensure that you make the changes in the order they are specified and do the operations on the updated String

Sentence 1:

• Make everything after the first word lowercase
• Remove the last space
• Remove the first 3 characters
• Change every z to an m
• Change every w to a space
• Find the first a and change it to a g

Sentence 2:

• Trim the extra white space from the sentence
• Replace every instance of asdf with the second character in the sentence

Take the first 8 characters and put them at the end of the sentence

Answer 1

If you have any problem with the code feel free to comment. Since no test cases were provided with the code, I was not able to test the program.

Program

import java.util.Scanner;

public class Test {
   public static void main(String[] args) {

       Scanner sc = new Scanner(System.in);

       // taking user input
       System.out.println("Enter the first Sentence: ");
       String first = sc.nextLine();

       System.out.println("Enter the second sentence: ");
       String second = sc.nextLine();

       System.out.println("Decode message 1: " + decodeMessage1(first));
       System.out.println("Decode message 2: " + decodeMessage2(second));

       sc.close();

   }

   public static String decodeMessage1(String msg) {

       // converting the entire sententence to lower case except first character
       String temp = msg;
       msg = msg.toLowerCase();
       msg = msg.replaceFirst(msg.charAt(0) + "", temp.charAt(0) + "");

       // remove the last space
       int lastSpaceIndex = msg.lastIndexOf(" ");
       String first = msg.substring(0, lastSpaceIndex);
       String second = msg.substring(lastSpaceIndex + 1, msg.length());
       msg = first + second;

       // remove first 3 characters
       msg = msg.substring(3, msg.length());

       // replace ever 'z' to 'm'
       msg = msg.replace('z', 'm');

       // change every 'w' to a space
       msg = msg.replaceAll("w", " ");

       // find first "a" and change it to "ag"
       msg = msg.replaceFirst("a", "a g");

       return msg;
   }

   public static String decodeMessage2(String msg) {

       // triming the extra space
       msg = msg.trim();

       // replacing all asdf with second character of the sentence
       msg = msg.replaceAll("asdf", msg.charAt(1) + "");

       // taking first 8 charcter and put them at the end of the sentence
       String first = msg.substring(0, 8);
       String second = msg.substring(8, msg.length());
       msg = second + first;

       return msg;
   }
}