Thread: How to calculate GPA

This is what I need to do.
When user type “grade,111111111,11111,A” assign a grade of A to the student, with RUID of 111111111, against course, with index of 11111.
4.1 View class will handle input and call CourseRegistrationController singleton object to get things done.
4.2 CourseRegistrationController.grade method will
4.2.1 First to call CourseOfferingContoller.getCourse method to get the Course object with index number of 11111.
4.2.2 It then call Course.grade method to assign grade to student with RUID of 111111111.
4.3 Course.grade method will get the Enrollment object from its Hashtable, with RUID of 111111111. And call Enrollment.setGrade to change the grade.

I have done all this, but kind of stuck of what to do next

Here is the last step 4.3

	// assign a grade to a student through 
	// roster list
public Enrollment grade(String RUID, String grade){
		Enrollment g = (Enrollment) enrollments.get(RUID);
		 g.setGrade(grade);
 
		return null;

enrollment class

public void setGrade(String grade) {
		this.grade = grade;
	}
	public String getGrade() {
		// when assign a grade to a student
		// you also need to recalculate GPA
 
 
		return grade;
	}

Im stuck on the "to change the grade." part. I am not sure where I store the grade for each course. I have 4 hash tables, one stores all the courses( index is course id and object is course name) one stores all students( index is student id and object is student name) one stores all the students in a class( index is course id and object is student name) and the other stores all the classes the one student is in. ( index is student id and object is course name)
But does not seem right.

In the course class, it has the method grade which says it // assign a grade to a student through roster list, but I don't see how since the index for that hashtable is the course id. How would I be able to find a particular student in the hashtable? Also how would I go about adding this grade? I was thinking something like this

	public Enrollment grade(String RUID, String grade){
		Enrollment g = (Enrollment) enrollments.get(RUID);
		 g.setGrade(grade);
		 enrollments.put(g.getCourse(), g );
		return null;

Then the gpa is stored in the hashtable with index being student id, but not sure how I would be able to view the grades in the other hashtable. I would assume using the enrollments.get but i am lost. To me it seems like it would be easier to just make another hashtable for grades and somehow have them linked or something. idk I am just confused.

thanks

Our professor told us to make 4 hashtables. I just don't really understand why but w.e lol

CourseOfferings class has the first hashtable you listed
StudentRecords class has second
course class has the third one
and student class has the fourth one
I have 8 classes in total with 3 packages, controller , view class model. theirs 3 classes in the controller 1 in view and 5 in model

was talking to a class mate and they said that

this already sets the grade into the has table, this is in the course class

public Enrollment grade(String RUID, String grade){
		Enrollment g = (Enrollment) enrollments.get(RUID);
		 g.setGrade(grade);
		return null;

does it seem right?

Here is my course class

String index;
	String name;
	// store roster list
		Hashtable enrollments= new Hashtable();
 
 
 
    public Course(String index, String name){
    	this.index = index;
    	this.name = name;
 
    }
 
	public String getIndex() {
		return index;
	}
 
	public String getName() {
		return name;
	}
 
 
	// add an enrollment to roster list
	public Enrollment addEnrollment(Enrollment e) {
		//put enrollment in hashtable
		enrollments.put(e.getCourse(), e );
		return e;
 
 
	}
 
	// remove an enrollment from roster list
	public Enrollment removeEnrollment(String RUID) {
 
		 enrollments.remove(RUID);
		return null;
	}
		// assign a grade to a student through 
	// roster list
	public Enrollment grade(String RUID, String grade){
		Enrollment g = (Enrollment) enrollments.get(RUID);
		 g.setGrade(grade);
			return null;
 
	}
 
 
}