Question

import java.util.*; /** Description: This program determines the average of a list of (nonnegative) exam scores. Repeats for more exams until the user says to stop. Input: Numbers, sum, answer Output: Displays program description Displays instruction for user Displays average Algorithm: 1. START 2. Declare variables sum, numberOf Students, nextNumber, answer 3. Display welcome message and program description 4. DOWHILE user wants to continue 5. Display instructions on how to use the program 6. Inititalize sum and number of student to 0 7. Get next number from keyboard 8. WHILE there are more numbers 9. Accumulate sum 10. Add 1 to number of students 11. Get next number 12. END WHILE 13. IF number of students > o 14. Display average 15. ELSE 16. Display message that no scores were entered 17. END IF 18 Ask user if they want to continue 19. Get answer 20. END DOWHILE 21. Display end of program message 22. STOP @author Sandra Perez @since 3/18/2015 */ public class ExamAveragerWhile //Name of class (same as name of program) { public static void main(String[] args) { //Declare variables double sum; //Declare variable for sum int numberOfStudents; //Declare variable for number of students double nextNumber; //Declare variable for next number String answer; //Declare variable for answer from user Scanner keyboard = new Scanner(System.in); //Set up Scanner to get data from keyborad //Display welcome message and description System.out.println("This Exam Averager program computes the average of"); System.out.println("a list of (nonnegative) exam scores."); //DoWhile user wants to continue do { System.out.println( ); //Display a blank line System.out.println("Enter all the exams to be averaged."); //Display instructions System.out.println("\nEnter a negative number after"); System.out.println("you have entered all the scores."); sum = 0; //Initialize sum to 0 numberOfStudents = 0;//Initialize number of students to 0 //Get next number from keyboard nextNumber = keyboard.nextDouble( ); //Loop to calculate the sum while (nextNumber >= 0) //Loop while there are more numbers //A negative number means no more numbers { sum = sum + nextNumber; //Accumulate sum numberOfStudents++; //Add 1 to number of students nextNumber = keyboard.nextDouble( ); //Get next number from keyboard } //End while if (numberOfStudents > 0) //If more students System.out.println("The average is " + (sum/numberOfStudents)); //Display the average else //No more students System.out.println("No grades to average."); //Else display message no grades //ENDIF //Asks user if there is another set of grades System.out.println("Do you want to average another set of grades?"); System.out.println("Enter yes or no."); //Get answer answer = keyboard.next( ); } while (answer.equalsIgnoreCase("yes")); //End of while loop when answer(ignore case) is yes //Display end of program message System.out.println("Thank you for using the Exam Averager!"); } //End of main } //End of class

instructions and directions are blow this point

The purpose of this assignment is to develop two programs:

1. A revised version of the ExamAveragerWhile.java program that is object oriented and uses methods as indicated below

2. A second testing program that will test various features of the program.

Problem Statement

Use  the ExamAveragerWhile.java program and make the following changes:

Revise the logic of the program to use methods for the following activities in the program:

1.1 displayWelcome()

1.2 displayInstructions()

1.3 getNextNumber()

1.4 calculateSum()

1.5 displayAverage()

1.6 displayThankyou()

2. Add a method to verify that numeric data is required.  

3. Your main() method will contain the basic logic of the program. You may want to add an additional method.

4. Add a comment with an appropriate name for your class. Make certain that you have revised your Javadoc comments to reflect the new logic for calling methods.

5. To make it clear name your program ExamAveragerWhileOOYourFirstInitialYourLastInitial.java

Directions

Create a folder named like Assignment6FirstnameLastname using your name.

Using the Template.java file create a Java program named ExamAveragerWhileOOTestYourFirstInitialYourLastInitial.java using your name and place it in your folder. Fill in the documentation at the top of the program including description, input, and output as well as the Javadoc tags.

Demonstrate that your program works by creating another testing program to cover the following situations (you will have to create a new object in your test program for each test situation):

3.1 Create a test case that demonstrates the features and use data test cases that includes:

a) no data is input

b) a negative number is input

c) three numbers input

3.2 Create a test case where the user enters text data instead of integers.

3.3 Create a test case where the users run the program a second time with a new set of data.

Note: You will need to create two programs one that has the basic class with methods as stated in the Problem Statement above and another testing program that uses various test cases. See Student.java and StudentTest.java for an example for creating test cases as we discussed in class.

4. Create a Word file named Assignment6MethodsProgramDocumentFirstnameLastname to complete the Program Design template including input, output, algorithm, and screenshots of your program running each of the 5 test cases and place it in your folder. At the end of your Program Design Document include a class diagram for this program. You can use drawi.io to create your class diagram as we did in class.

Answer 1

import java.util.Scanner;

// Name of class (same as name of program)
// Defines class ScoreAveragerWhile
class ScoreAveragerWhile
{
   // Declare instance variables
   // Declare variable for sum
   double sum;
   // Declare variable for number of students
   int numberOfStudents;
   // Declare variable for next number
   double nextNumber;  
  
   // Set up Scanner to get data from keyborad
   Scanner keyboard = new Scanner(System.in);
  
   // Method to display welcome message
   void displayWelcome()
   {
       // Display welcome message and description
       System.out.print("\n ********* Welcome to Average Calculater ********* ");
       System.out.print("\n This Averager program computes the average of");
       System.out.print(" \n a list of (nonnegative) scores.");
   }// End of method
  
   // Method to display instruction
   void displayInstructions()
   {
       System.out.print("\n\n ********* Instruction to user ********* ");
       //Display a blank line
       System.out.print("\n Enter all the score to be averaged.");
       //Display instructions
       System.out.print("\n Enter a negative number after");
       System.out.print(" you have entered all the scores.\n");
   }// End of method
  
   // Method to accept score  
   void getNextNumber()
   {
       System.out.print("\n Enter score: ");
       // Get next number from keyboard
       nextNumber = keyboard.nextDouble( );
   }// End of method
  
   // Method to to calculate sum  
   void calculateSum()
   {
       // Loop to calculate the sum
       // Loop while there are more numbers
       // A negative number means no more numbers
       while (nextNumber >= 0)             
       {
           // Accumulate sum
           sum = sum + nextNumber;
           // Increase the number of student by one
           numberOfStudents++;
           // Calls the method to accept score
           getNextNumber();
          
       } //End while
   }// End of method
  
   // Method to calculate and display average  
   void displayAverage()
   {
       // If more students
       if (numberOfStudents > 0)
           // Display the average
           System.out.print("\n The average is " + (sum / numberOfStudents));
       // No more students
       else
           // Else display message no grades
           System.out.print("\n No grades to average.");             
       // ENDIF
   }// End of method
  
   // Method to display thanks message  
   void displayThankyou()
   {
       // Display end of program message
       System.out.println("Thank you for using the Score Averager App!");
   }// End of method         
}// End of class

// Driver class definition
public class ScoreAveragerWhileTest
{
   // main method definition
   public static void main(String[] args)
   {
       // Creates an object of class ExamAveragerWhile
       ScoreAveragerWhile eaw = new ScoreAveragerWhile();
       // Declare variable for answer from user
       String answer;

       // Calls the method to display welcome message
       eaw.displayWelcome();
      
       // Calls the method to display instruction
       eaw.displayInstructions();
      
       // DoWhile user wants to continue
       do
       {
           // Initialize sum to 0  
           eaw.sum = 0;
           // Initialize number of students to 0
           eaw.numberOfStudents = 0;
           // Calls the method to accept score
           eaw.getNextNumber();
           // Calls the method to calculate sum
           eaw.calculateSum();
           // Calls the method to calculate average and displays it
           eaw.displayAverage();
          
           // Asks user if there is another set of grades
           System.out.print("\n Do you want to average another set of grades? ");
           System.out.println("\n Enter yes or no.");
           // Get answer
           answer = eaw.keyboard.next( );
       } while (answer.equalsIgnoreCase("yes"));
       // End of while loop when answer(ignore case) is yes
      
       // Calls the method to display thanks message
       eaw.displayThankyou();
   } //End of main
}// End of driver class

Sample Output:

********* Welcome to Average Calculater *********
This Averager program computes the average of
a list of (nonnegative) scores.

********* Instruction to user *********
Enter all the score to be averaged.
Enter a negative number after you have entered all the scores.

Enter score: 10.0

Enter score: 20.0

Enter score: 30.0

Enter score: -3

The average is 20.0
Do you want to average another set of grades?
Enter yes or no.
yes

Enter score: -8

No grades to average.
Do you want to average another set of grades?
Enter yes or no.
yes

Enter score: 45.6

Enter score: 33.7

Enter score: 89.4

Enter score: 66.6

Enter score: 12.1

Enter score: -7

The average is 49.480000000000004
Do you want to average another set of grades?
Enter yes or no.
no
Thank you for using the Score Averager App!