Question

Write a class encapsulating the concept of a Student, assuming that a student has the following attributes: last name, first name, id, array of grades. Include a constructor, the accessors and mutators, and method toString. Also code the following methods: one returning the GPA using the array of grades (assuming each grade represents a course grade and all courses have the same number of credit hours) and a method to add a course grade to the array of grades (this means creating a larger array). Write a client class to create 2 student objects and test all your methods.

Answer 1

Student.java

public class Student {
   // instance variables
   private int id;
   private String firstName;
   private String lastName;
   private double[] grades=new double[10]; // grades array
   private static int courseCount=0; // variable to keep record of grades array
   // default constructor
   public Student() {
       super();
       courseCount=0;
   }
   // parameterized constructor
   public Student(int id, String firstName, String lastName) {
       super();
       this.id = id;
       this.firstName = firstName;
       this.lastName = lastName;
       courseCount=0;
   }
   // setters and getters
   public int getId() {
       return id;
   }
   public void setId(int id) {
       this.id = id;
   }
   public String getFirstName() {
       return firstName;
   }
   public void setFirstName(String firstName) {
       this.firstName = firstName;
   }
   public String getLastName() {
       return lastName;
   }
   public void setLastName(String lastName) {
       this.lastName = lastName;
   }
   // method to calculate GPA
   public double getGPA() {
       double total = 0;
       for(int i=0;i<courseCount;i++) {
           total+=grades[i];
       }
       return total/courseCount;
   }
   // method to add course grade into grades array
   public void addCourseGrade(double grade) {
       grades[courseCount]=grade;
       courseCount++;
   }
   // method to get grades to display
   public String displayGrades() {
       String gradeString="";
       for(int i=0;i<courseCount;i++)
           gradeString=gradeString+" "+grades[i];
       return gradeString;
   }
   @Override
   public String toString() {
       return "\nStudent:"
               + "\nId: "+id
               +"\nFirst Name: "+firstName
               +"\nLast Name: "+lastName
               +"\nGrades: "+displayGrades();
   }
  
}

StudentClient.java

public class StudentClient {
   public static void main(String[] args) {
       // create Student object
       Student student1=new Student(101, "Steve", "Rogers");
       student1.addCourseGrade(95); // add course grade
       student1.addCourseGrade(82);
       student1.addCourseGrade(93);
       System.out.println(student1); // print student details
       System.out.println("GPA: "+student1.getGPA()); // display GPA
      
       Student student2=new Student(102,"Rabia","Hasan");
       student2.addCourseGrade(75);
       student2.addCourseGrade(83);
       student2.addCourseGrade(74);
       System.out.println(student2);
       System.out.println("GPA: "+student2.getGPA());
      
   }
}

Output