How do I add an object to a list in another class?

Question

I find myself unable to implement critical sections of my code for a project. The assignment is to develop the backend a text-based gradebook. I have a method, addStudent, which is supposed to add a student to a list in a section, also contained in a list.

I have a method in the Gradebook class, addStudent, which is supposed to add a student object to a list contained within the current Section object. The sections are also contained in a list. I have tried all sorts of combinations, but I can't seem to find the magic words that actually let me accomplish this.

The file is defined in 5 files/classes; Assignment(can be ignored for now), Student, Section, Gradebook, Program (also can ignore, only used for front end (input to pass to mehtods, etc.)).

Here is the method I need to implement, contained in the Gradebook class.

public bool addStudent(string firstName, string lastName, string username, long phoneNumber)
        {

            return false; //FIXME
        }

Here is the Section Class:

class Section
    {
        string sectionName;
        //probably more properties need to be implemented, or at least would make life simpler
        public Section(string sectionName)
        {
            this.sectionName = sectionName;
            List<Student> students = new List<Student>();
            List<Assignment> assignments = new List<Assignment>();
        }    
    }

Here is the Student Class:

class Student
    {
        string firstName = null;
        string lastName = null;
        long studentID = 0;
        long phoneNumber = 0;
        int absentcount = 0;
        int tardyCount = 0;
        double gradePercent = 0;
        //need to add more properties, read through Gradebook API for more

        public Student(string firstName, string lastName, long studentID, long phoneNumber)
        {
            this.firstName = firstName;
            this.lastName = lastName;
            this.studentID = studentID;
            this.phoneNumber = phoneNumber;
            List<Assignment> studentAssignments = new List<Assignment>();
        }

I am aware of the duplicate assignment definitions, I am keeping both in for now, likely for redundancy, though this might not be a great idea, in which case I will only keep the student version.

I expect to be able to just add some longer line referencing each object in the respective lists, but I always come up with an error, either that I need to make the fields read only, or that the object doesn't exist. The only solution I can think of would be to keep an index for the last modified element in the list, but I'd rather not do that.

I would logically think to do something like this (I know this is wrong): currentSection.Student.Add(Student(firstName, lastName, username, phoneNumber)) . I know this can't be though, because I need to refernce the list element, not the class itself.

I also may just be overthinking this quite a bit but any help would be appreciated.

Answer 1

You should make your List<Student> students accessible from outside your Session constructor

Change your Section declaration to:

class Section
{
    string sectionName;
    public List<Student> students;

    //probably more properties need to be implemented, or at least would make life simpler
    public Section(string sectionName)
    {
        this.sectionName = sectionName;
        students = new List<Student>();
        List<Assignment> assignments = new List<Assignment>();
    }    
}

Add the student to your list with

currentSection.students.Add(new Student(firstName, lastName, username, phoneNumber));