Question

Write a complete Java code that contain two classes. A GradeBook and a GradeBookTester.

- The GradeBook class contains the followings:

- An array of grades (integer array) declared as a field.

- A constructor that takes an integer value as parameter (len), and creates the grades array of size equals to len.

- A method called fillArray that fills the grades array with random integers. Acceptable values are between 1 and 100 (inclusive)

- A method called printStatistics that prints 4 values: the average of the grades, the minimum grade, the maximum grade, and the median grade (the middle value of the sorted array).

- The GradeBookTester contains the main and do the followings:

- Uses the input dialog to ask the user to enter an integer value (assume that the user will enter a value that is non-zero and positive / no need to check)

- creates an object of GradeBook class while passing the entered value as parameter.

- calls the functions fillArray and printStatistics for testing.

Please Solve As soon as

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Thank's

Answer 1

GradeBook.java

import java.util.Random;

public class GradeBook {

    private int grades[];

    public GradeBook(int size) {

        grades = new int[size];

    }

    // method to fill the array

    public void fillArray() {

        Random rn=new Random();

        // loop through the array and randomly fill it

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

            grades[i] = rn.nextInt(100) + 1;

        }

    }

    // print the statistics of the array values

    public void printStatistics() {

        int max = grades[0], min = grades[0];

        float avg=0, median=0;

        // loop through the array

        for (int a : grades) {

            if (a < min)

                min = a;

            if (a > max)

                max = a;

            avg += a;

        }

        avg = avg / grades.length;

        // sort the array

        for (int i = 0; i < grades.length - 1; i++) {

            for (int j = 0; j < grades.length - i - 1; j++) {

                if (grades[j] > grades[j + 1]) {

                    int t = grades[j];

                    grades[j] = grades[j + 1];

                    grades[j + 1] = t;

                }

            }

        }

        int l = grades.length;

        median = l % 2 == 0 ? (grades[l / 2] + grades[l / 2 + 1]) / 2 : grades[l / 2];

        System.out.println("Minimum : " + min + "\nMaximum : " + max + "\nAverage : " + avg + "\n Median : " + median);

    }

}

Screenshot

GradeBookTester.java

import java.util.*;

public class GradeBookTester {

    public static void main(String args[]) {

        Scanner x = new Scanner(System.in);

        // get user input

        System.out.print("Enter size of grades array : ");

        int l = Integer.parseInt(x.nextLine());

        // call GradeBook methods

        GradeBook grade = new GradeBook(l);

        grade.fillArray();

        grade.printStatistics();

    }

}

SCreenshot

Output