diff --git a/src/main/java/io/zipcoder/Classroom.java b/src/main/java/io/zipcoder/Classroom.java
index 64566f0..5632083 100644
--- a/src/main/java/io/zipcoder/Classroom.java
+++ b/src/main/java/io/zipcoder/Classroom.java
@@ -1,4 +1,122 @@
 package io.zipcoder;
 
+import java.util.*;
+
 public class Classroom {
+    //declare the instance variables
+
+    Student[] students;
+    int maxNumberOfStudents;
+    ArrayList<Student> studentList;
+
+    //1st constructor
+    public Classroom(int max) {
+        this.maxNumberOfStudents = max;
+        students=new Student[max];
+        studentList=new ArrayList<>();
+    }
+
+
+    //2nd constructor
+    //here student is the object in Student[]
+    public Classroom(Student[] students) {
+        this.students = students;
+    }
+
+
+    //3rd constructor
+    public Classroom() {
+        studentList=new ArrayList<>();
+        students=new Student[30];
+
+
+    }
+
+    //define a method getStudent()
+    public Student[] getStudents() {
+        return students;
+    }
+
+    //get average exam score
+    public Double getAverageExamScore() {
+
+
+        double total = 0;
+        for (Student s : students) {
+            if (s != null)
+                total = total + s.averageExamScore();
+        }
+
+        Double average = total / students.length;
+        return average;
+    }
+
+    //define method add student
+
+    public void addStudent(Student student) {
+
+        for (int i = 0; i < students.length; i++) {
+            if(students[i]==null){
+                students[i]=student;
+                break;
+            }
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "Classroom{" +
+                "students=" + Arrays.toString(students) +
+                ", maxNumberOfStudents=" + maxNumberOfStudents +
+                '}';
+    }
+
+
+
+    public void removeStudent(String firstName ,String lastName) {
+        List<Student> studentsList = new ArrayList<>();
+        if(this.students !=null) {
+            studentsList = new ArrayList<>(Arrays.asList(this.students));
+        }
+        for(Student student : studentsList) {
+            if(student.getFirstName().equals(firstName) && student.getLastName().equals(lastName)) {
+                studentsList.remove(student);
+                break;
+            }
+        }
+        this.students = studentsList.toArray(new Student[]{});
+
+    }
+    public Student getStudentsByScore(Student[] students){
+        Arrays.sort(students, Collections.reverseOrder());
+
+
+        return null;
+    }
+    public Map<Student, String> getGradebook() {
+        Map<Student, String> gradebook = new HashMap<>();
+        String grade = "";
+        for (Student student : students) {
+            if (student.averageExamScore() >= 90)
+                grade = "A";
+            else if (student.averageExamScore() >= 80)
+                grade = "B";
+            else if (student.averageExamScore() >= 70)
+                grade = "C";
+            else if (student.averageExamScore() >= 60)
+                grade = "D";
+            else
+                grade = "F";
+            gradebook.put(student, grade);
+        }
+        return gradebook;
+    }
+
+
+
+
+
 }
+
+
+
diff --git a/src/main/java/io/zipcoder/Student.java b/src/main/java/io/zipcoder/Student.java
index b543e36..1961dd5 100644
--- a/src/main/java/io/zipcoder/Student.java
+++ b/src/main/java/io/zipcoder/Student.java
@@ -1,4 +1,100 @@
 package io.zipcoder;
 
-public class Student {
+import java.util.ArrayList;
+import java.util.Arrays;
+
+public class Student implements Comparable<Student>{
+    String firstName;
+    String lastName;
+    ArrayList<Double> examScore;
+
+
+
+    Student(String firstName , String lastName , Double[] testScores){
+        this.firstName=firstName;
+        this.lastName=lastName;
+        this.examScore= new ArrayList<Double>(Arrays.asList(testScores));
+
+    }
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public ArrayList<Double> getExamScore() {
+        return examScore;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+
+    public Integer getNumberOfExamsTaken(){
+        if(this.examScore!= null){
+            return examScore.size();
+        }
+        else return 0;
+    }
+
+
+    public String getExamScores() {
+        StringBuilder output=new StringBuilder();
+        output.append("Exam Scores:\n");
+        for(int i=0;i<examScore.size();i++){
+            output.append(String.format("\tExam %s -> %s\n",i+1,Math.round(examScore.get(i))));
+        }
+        return output.toString();
+    }
+
+    /*
+    public String getExamScores(){
+        String output="Exam Scores:\n";
+        for(int i=0;i<examScore.size();i++){
+            output=output+String.format("Exam %s -> %s\n",i+1,Math.round(examScore.get(i)));
+        }
+        System.out.println(output);
+        return output;
+    }
+    */
+
+    public void addExamScore(Double examScore){
+        this.examScore.add(examScore);
+
+    }
+    public void setExamScore(int examNumber, double newScore){
+        this.examScore.set(examNumber-1,newScore);
+    }
+
+
+    public Integer averageExamScore(){
+        Double sum=0.0;
+        for(int i=0;i<this.examScore.size();i++){
+            sum=(sum+this.examScore.get(i));
+
+        }
+        int avg=(int)Math.rint(sum/this.examScore.size());
+        return avg;
+    }
+    @Override
+    public String toString(){
+        return "Student Name: "+firstName+" "+lastName+"\n> Average Score: "+averageExamScore()+"\n> "+getExamScores();
+
+
+    }
+
+
+    ArrayList<Student>studentArrayList=new  ArrayList<>();
+
+    @Override
+    public int compareTo(Student o) {
+        return 0;
+    }
 }
diff --git a/src/test/java/io/zipcoder/ClassroomTest.java b/src/test/java/io/zipcoder/ClassroomTest.java
index 7bac1ff..ae3bead 100644
--- a/src/test/java/io/zipcoder/ClassroomTest.java
+++ b/src/test/java/io/zipcoder/ClassroomTest.java
@@ -1,4 +1,171 @@
 package io.zipcoder;
 
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Map;
+
 public class ClassroomTest {
+    @Test
+    public void ClassroomTest() {
+        Double[] s1Scores = {100.0, 150.0};
+        Double[] s2Scores = {225.0, 25.0};
+        Student s1 = new Student("student", "one", s1Scores);
+        Student s2 = new Student("student", "two", s2Scores);
+        Student[] students = new Student[]{s1, s2};
+        Classroom classroom = new Classroom(students);
+        Student[] actual = classroom.getStudents();
+        Assert.assertEquals(students, actual);
+    }
+
+    @Test
+    public void getAverageExamScoreTest() {
+        Double[] s1Scores = {100.0, 150.0};
+        Double[] s2Scores = {225.0, 25.0};
+
+        Student s1 = new Student("Rose", "Petal", s1Scores);
+        Student s2 = new Student("Subhash", "Bose", s2Scores);
+        Student[] students = new Student[]{s1, s2};
+        Classroom classroom = new Classroom(students);
+        Double expected = 125.0;
+        Double actual = classroom.getAverageExamScore();
+
+
+        Assert.assertEquals(expected, actual);
+
+    }
+
+    @Test
+    public void test2getAverageExamScore() {
+        Double[] s1Scores = {100.0, 95.0};
+        Double[] s2Scores = {100.0, 96.0};
+        Student s1 = new Student("Student", "one", s1Scores);
+        Student s2 = new Student("Student", "two", s2Scores);
+        Student[] students = new Student[]{s1, s2};
+        Classroom classroom = new Classroom(students);
+        Double actual = classroom.getAverageExamScore();
+        System.out.println(actual);
+        Assert.assertNotEquals(100, classroom.getAverageExamScore(), 0.00009);
+
+    }
+
+    @Test
+    public void addStudentTest() {
+        // : Given
+        int maxNumberOfStudents = 1;
+        Classroom classroom = new Classroom(maxNumberOfStudents);
+        Double[] examScores = {100.0, 150.0, 250.0, 0.0};
+        Student student = new Student("Leon", "Hunter", examScores);
+
+        // When
+        Student[] preEnrollment = classroom.getStudents();
+        System.out.println(classroom.toString());
+        classroom.addStudent(student);
+        Student[] postEnrollment = classroom.getStudents();
+
+        // Then
+        String preEnrollmentAsString = Arrays.toString(preEnrollment);
+        String postEnrollmentAsString = Arrays.toString(postEnrollment);
+
+        System.out.println("===========================");
+        System.out.println(preEnrollmentAsString);
+        System.out.println("===========================");
+        System.out.println(postEnrollmentAsString);
+    }
+
+
+    @Test
+    public void removeStudentTest() {
+        Double[] s1Scores = {100.0, 150.0};
+        Double[] s2Scores = {225.0, 25.0};
+        Double[] s3Scores = {98.0, 112.0};
+        Double[] s4Scores = {220.0, 45.0};
+        Student s1 = new Student("Student", "one", s1Scores);
+        Student s2 = new Student("Rose", "Petal", s2Scores);
+        Student s3 = new Student("Student", "three", s3Scores);
+        Student s4 = new Student("Student", "four", s4Scores);
+
+        String firstName = "Rose";
+        String lastName = "Petal";
+        Classroom classroom = new Classroom();
+        classroom.addStudent(s1);
+        classroom.addStudent(s2);
+        classroom.addStudent(s3);
+        classroom.addStudent(s4);
+        Student[] students = new Student[]{s1, s2, s3, s4};
+
+
+        classroom.removeStudent("Rose", "Petal");
+        Student[] expected = classroom.getStudents();
+        Assert.assertEquals(s1, expected[0]);
+        Assert.assertEquals(s3, expected[1]);
+        Assert.assertEquals(s4, expected[2]);
+        Assert.assertEquals(expected[3], null);
+        // System.out.println(expected[3]);
+        //Assert.assertEquals(expected[3]);
+
+
+    }
+
+    /*
+    @Test
+        public void getStudentByScoreTest(){
+        Double[] s1Scores = { 100.0, 150.0 };
+        Double[] s2Scores = { 225.0, 25.0 };
+        Double[] s3Scores = { 98.0, 112.0 };
+        Double[] s4Scores = { 220.0, 45.0 };
+        Student s1=new Student("Student", "one", s1Scores);
+        Student s2=new Student("Student", "two", s2Scores);
+        Student s3=new Student("Student", "tree", s1Scores);
+        Student s4=new Student("Student", "four", s2Scores);
+        Student[] students=new Student[]{s1,s2,s3,s4};
+        Classroom classroom =new Classroom(students);
+        Student[] expected = {s4, s2,s1,s3};
+        Student[] actual=classroom.getStudentsByScore( Student[] Students);
+        Assert.assertArrayEquals(expected, actual);
+
+        }*/
+    @Test
+    public void getStudentsByScoreTest() {
+        Double[] scores1 = new Double[]{45.0, 50.0, 55.0};
+        Double[] scores2 = new Double[]{60.0, 65.0};
+        Double[] scores3 = new Double[]{70.0, 70.0};
+        Student student1 = new Student("Jimmy", "John", scores1);
+        Student student2 = new Student("Tammy", "Tohn", scores2);
+        Student student3 = new Student("Jack", "Tohn", scores3);
+        Student[] newStudents = {student1, student2, student3};
+        Classroom classroom = new Classroom(newStudents);
+
+    }
+    @Test
+    public void getGradebookTest() {
+       /* int n = 20;
+        Student[] students = new Student[n];
+        for (int i = 1; i<=n; i++) {
+            students[i-1] = new Student("","",new Double[] {100.0,5.0*i});
+        }
+        Classroom classroom = new Classroom(students);*/
+        Double[] scores1 = new Double[] {45.0, 50.0, 55.0};
+        Double[] scores2 = new Double[] {60.0, 65.0};
+        Double[] scores3 = new Double[] {70.0, 70.0};
+        Double[] scores4 = new Double[] {95.0, 90.0, 95.0};
+        Double[] scores5 = new Double[] {80.0, 85.0};
+        Student student1 = new Student("Jimmy", "John", scores1 );
+        Student student2 = new Student("Tammy", "Tohn", scores2 );
+        Student student3 = new Student("Jack", "Tohn", scores3 );
+        Student student4 = new Student("Rhett", "Ale", scores4 );
+        Student student5 = new Student("Amy", "Roberts", scores5 );
+        Student[] newStudents = {student1, student2, student3, student4, student5};
+        Classroom classroom = new Classroom(newStudents);
+
+        Map<Student,String> gradebook = classroom.getGradebook();
+
+        Assert.assertEquals(gradebook.get(student1),"F");
+        Assert.assertEquals(gradebook.get(student2),"D");
+        Assert.assertEquals(gradebook.get(student3),"C");
+        Assert.assertEquals(gradebook.get(student4),"A");
+        Assert.assertEquals(gradebook.get(student5),"B");
+
+    }
 }
diff --git a/src/test/java/io/zipcoder/StudentTest.java b/src/test/java/io/zipcoder/StudentTest.java
index a9fedec..ef0f7ce 100644
--- a/src/test/java/io/zipcoder/StudentTest.java
+++ b/src/test/java/io/zipcoder/StudentTest.java
@@ -1,5 +1,98 @@
 package io.zipcoder;
 
+import org.junit.Assert;
+import org.junit.Test;
+
 public class StudentTest {
+    @Test
+    public void testDefaultConstructor() {
+        // Given
+        String expectedfirstName = "Rose";
+        String expectedlastName  = "Petal";
+        // ArrayList<Double> examScore =  new ArrayList<>();
+        Double[] examScores = { 100.0, 95.0, 123.0, 96.0 };
+        String examScoresStr = "Exam Scores:\n" +
+                "\tExam 1 -> 100\n"  +
+                "\tExam 2 -> 95\n" +
+                "\tExam 3 -> 123\n" +
+                "\tExam 4 -> 96\n";
+
+        // When
+        Student student = new Student(expectedfirstName,expectedlastName, examScores);
+
+        // Then
+        String actualFirstName = student.getFirstName();
+        String actualLastName = student.getLastName();
+        String actualScore = student.getExamScores();
+
+        Assert.assertEquals(expectedfirstName, actualFirstName);
+        Assert.assertEquals(expectedlastName, actualLastName);
+        Assert.assertEquals(examScoresStr, actualScore);
+    }
+
+    @Test
+    public void addExamScoreTest(){
+        String expectedFirstName = "Leon";
+        String expectedLastName = "Hunter";
+        Double[] expectedExamScores = { };
+        Student student = new Student(expectedFirstName,expectedLastName, expectedExamScores);
+        student.addExamScore(100.0);
+        String actual = student.getExamScores();
+        System.out.println(actual);
+        String expected="Exam Scores:\n"+"\tExam 1 -> 100\n";
+        System.out.println(expected);
+        Assert.assertEquals(expected,actual);
+
+    }
+    @Test
+    public void setExamScoreTest(){
+        String expectedFirstName = "Leon";
+        String expectedLastName = "Hunter";
+        Double[] expectedExamScores = { 100.0,50.0,23.0};
+        Student student = new Student(expectedFirstName,expectedLastName,expectedExamScores);
+        student.setExamScore(2, 150.0);
+        String actual = student.getExamScores();
+        System.out.println(actual);
+        String expected="Exam Scores:\n"+"\tExam 1 -> 100\n"+"\tExam 2 -> 150\n"+"\tExam 3 -> 23\n";
+        Assert.assertEquals(expected,actual);
+    }
+
+    @Test
+    public void getExamScoreTest(){
+        String firstName="Lad";
+        String lastName="Drummand";
+        Double[] examScores = { 100.0,95.0,123.0,96.0};
+        Student student = new Student(firstName,lastName,examScores);
+        String actual=student.getExamScores();
+        System.out.println(actual);
+        String expected="Exam Scores:\n"+"\tExam 1 -> 100\n"+"\tExam 2 -> 95\n"+"\tExam 3 -> 123\n"+"\tExam 4 -> 96\n";
+        System.out.println(expected);
+        Assert.assertEquals(expected,actual);
+
+
+    }
+    @Test
+    public void getAverageExamScoreTest(){
+        String expectedFirstName = "Leon";
+        String expectedLastName = "Hunter";
+        Double[] expectedExamScores = { 100.0, 150.0, 250.0,0.0 };
+        Student student = new Student(expectedFirstName, expectedLastName,expectedExamScores);
+        int expected=125;
+        int actual = student.averageExamScore();
+        System.out.println(actual);
+        Assert.assertEquals(expected,actual);
+    }
+
+    @Test
+    public void toStringTest() {
+        String firstName = "Leon";
+        String lastName = "Hunter";
+        Double[] examScores = {100.0, 150.0, 250.0, 0.0 };
+        Student student = new Student(firstName, lastName, examScores);
+        String actual = student.toString();
+        String expected="Student Name: Leon Hunter\n"+"> Average Score: 125\n"+"> Exam Scores:\n"
+                +"\tExam 1 -> 100\n"+"\tExam 2 -> 150\n"+"\tExam 3 -> 250\n"+"\tExam 4 -> 0\n";
+        Assert.assertEquals(expected,actual);
+    }
 
 }
\ No newline at end of file
diff --git a/target/classes/io/zipcoder/Classroom.class b/target/classes/io/zipcoder/Classroom.class
new file mode 100644
index 0000000..9d5caed
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diff --git a/target/classes/io/zipcoder/Student.class b/target/classes/io/zipcoder/Student.class
new file mode 100644
index 0000000..a28dd84
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diff --git a/target/test-classes/io/zipcoder/ClassroomTest.class b/target/test-classes/io/zipcoder/ClassroomTest.class
new file mode 100644
index 0000000..0883d33
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diff --git a/target/test-classes/io/zipcoder/StudentTest.class b/target/test-classes/io/zipcoder/StudentTest.class
new file mode 100644
index 0000000..456c015
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