Question

Java Programming

THE PROBLEM: At the beginning of each online meeting, the instructor randomly greets a student whose camera is on. That student greets, also at random, another student whose camera is on. This chain continues until there is only one student with the camera on. That student says hello to the instructor, concluding the hello chain.

A lot of things can go wrong during the hello chain. For example a student's audio may be muffled, muted, or noisy. We can't tell who the student greeted, i.e., we don't know who's the next link in this hello chain. Likewise, the student who has been greeted may not have heard their name. Or a student greets, by mistake, a student whose camera is turned off, etc.

Design and write a HelloChain class to simulate the situation above. Where there are issues in the hello chain but then you have to fix them. This can be done with a random name generator. Your class must be based on a data structure of your choice. Don't pile everything in the main method.

Answer 1

TRY RUNNING FOR DIFFERENT OUTPUTS

JAVA CODE:

import java.util.*;

public class HelloChain{

   static Random rand = new Random();
   // Creating random object to get the random replies
   static ArrayList<String> students;
   // List of students in the meeting
   static ArrayList<String> students_message = new ArrayList<String>();
   // List of possible replies of student
   static String random_students_message;
   // Variable to store random student reply

   public static void main(String[] args) {
       int i;
       Scanner reader = new Scanner(System.in);

       System.out.println("How many students are there in the meeting?");
       int number_of_students = reader.nextInt();
       // Input number of students in the meeting

       System.out.println("Enter the names of all the students");

       students = new ArrayList<String>();
       // Initializing students arraylist

       for (i = 0; i < number_of_students; i++) {
           System.out.print(i + 1);
           students.add(reader.next());
           // Adding student name to the list
       }

       System.out.println("Students present in the meeting are : \n" + students);

       get_tutor_message(students, number_of_students);
       // Calling method to get the message from the instructor
   }

   private static void get_tutor_message(ArrayList<String> students, int number_of_students) {

       ArrayList<String> tutormessage = new ArrayList<String>();
       // List of 3 possible instructor messages
       // blank
       // hello
       // hello any student name(generated using the random function)
       tutormessage.add("");
       tutormessage.add("hello");
       tutormessage.add("hello " + students.get(rand.nextInt(students.size())));

       String tutor_random_message = tutormessage.get(rand.nextInt(tutormessage.size()));
       System.out.println("Tutor Greeting ........\n" + tutor_random_message);
       // Printing instructors message

       try {
           if (tutor_random_message.equals("")) {
               System.out.println("No greetings from the Instructor.");

           } else
               get_student_message(tutor_random_message);
           // sending instructors message to get reply from the student
       }

       catch (ArrayIndexOutOfBoundsException e) {
           System.out.println("No more Students left for meeting");
       }

   }

//Method to get student responses
   private static void get_student_message(String tutor_random_message) {

       // If last student is remaining or no one is speaking
       if (students.size() == 1 || tutor_random_message.equals("")) {
           System.out.println((students.get(0) + " replying.......\n Hello Teacher"));
       }

       else if (tutor_random_message.equals("hello")) {

           // if only hello is received ,without referral
           // Then it can be answered by any random student
           // student's 3 possible responses are added to students message list
           students_message.add("");
           students_message.add("hello");
           students_message.add("hello " + students.get(rand.nextInt(students.size())));

           String random_student = students.get(rand.nextInt(students.size()));
           // Once replied the student is removed from the greeting that is students list
           students.remove(random_student);
           // method to print message of random_student
           print_message(random_student);

       }

       else {
           // if hello + student name is received
           String student_name = tutor_random_message.substring(tutor_random_message.indexOf(" ") + 1,
                   tutor_random_message.length());
           // Student name is taken out from the "hello student" by applying substring
           // function
           students.remove(student_name);
           // Once replied the student is removed from the greeting that is students list

           print_message(student_name);
           // method to print message of random_student

       }

   }

   private static void print_message(String student) {

       System.out.println(student + " replying..........");
       random_students_message = students_message.get(rand.nextInt(students_message.size()));
       // Picking up the randim message from the students_message list
       System.out.println(random_students_message);
       get_student_message(random_students_message);
       // Again calling the get_student_message to continue the process

   }

}

OUTPUT: