Write a class encapsulating the concept of student grades on a test, assuming st

Question

Write a class encapsulating the concept of student grades on a test, assuming student grades are composed of a list of integers between 0 and 100.

Write the following methods:

--A constructor with just one parameter, the number of students; all grades will be randomly generated.

--Accessor, mutator, toString and equals methods

--A method returning an array of the grades sorted in ascending order.

--A method returning the highest grade

--a method returning the average grade

--a method returning the median grade[Hint: the median grade will be located in the middle of the sorted array of grades]

--A method returning the mode(the grade that occurs the most often)(Hint: create an array of counters; count how many times each grade occurs; then pick the maximum in the array of counters; the array index in the array of counter should correspond to the same index in the array of grades - use that index to find the grade value that is the mode)

Write a client class to test all your methods.

Explanation / Answer

GradeStats.java

import java.util.*;

public class GradeStats {

   private int[] grades;
   private int numberOfStudents;

   public GradeStats(int numberOfStudents) {
       this.numberOfStudents = numberOfStudents;
       grades = new int[numberOfStudents];
       for (int i = 0; i < numberOfStudents; ++i) {
           grades[i] = (int) (Math.random() * 101);
       }
   }

   public int[] getSortedGrades() {
       int[] sorted = this.grades.clone();
       Arrays.sort(sorted);
       return sorted;
   }

   public int getHighestGrade() {
       int max = -1;
       for (int i = 0; i < numberOfStudents; ++i) {
           max = Math.max(max, grades[i]);
       }
       return max;
   }

   public double getAverageGrade() {
       double sum = 0.0;
       for (int i = 0; i < numberOfStudents; ++i) {
           sum += grades[i];
       }
       return sum / numberOfStudents;
   }

   public int getMedianGrade() {
       int[] sorted = getSortedGrades();
       if (numberOfStudents % 2 == 0) {
           int half = numberOfStudents / 2;
           return (sorted[half] + sorted[half - 1]) / 2;
       } else {
           return sorted[(numberOfStudents + 1) / 2];
       }
   }

   public int getModeGrade() {
       int[] sorted = getSortedGrades();
       int i = 0;
       int mode = -1;
       int maxTillNow = -1;
       while (i < numberOfStudents) {
           int count = 0;
           int current = sorted[i];
           while (i < numberOfStudents && sorted[i] == current) {
               ++i;
               ++count;
           }
           if (count > maxTillNow) {
               mode = current;
               maxTillNow = count;
           }
       }
       return mode;
   }

   public int[] getGrades() {
       return this.grades;
   }

   public void setGrades(int[] grades) {
       this.grades = grades;
   }

   @Override
   public String toString() {
       return "Grades: " + grades.toString();
   }

   public boolean equals(GradeStats b) {
       if (this.numberOfStudents == b.numberOfStudents) {
           for (int i = 0; i < numberOfStudents; ++i) {
               if (this.grades[i] != b.getGrades()[i]) {
                   return false;
               }
           }
           return true;
       } else {
           return false;
       }
   }
}

Main.java

public class Main {

   public static void main(String[] args) {
       GradeStats gs = new GradeStats(10);

       System.out.print("Grades: ");
       int[] grades = gs.getGrades();
       for (int i = 0; i < grades.length; ++i) {
           System.out.print(grades[i] + " ");
       }
       System.out.println();

       System.out.print("Sorted Grades: ");
       int[] sortedGrades = gs.getSortedGrades();
       for (int i = 0; i < sortedGrades.length; ++i) {
           System.out.print(sortedGrades[i] + " ");
       }
       System.out.println();

       System.out.println("Highest Grade: " + gs.getHighestGrade());

       System.out.println("Average Grade: " + gs.getAverageGrade());

       System.out.println("Median Grade: " + gs.getMedianGrade());

       System.out.println("Mode Grade: " + gs.getModeGrade());
   }
}

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