import java.util.ArrayList;

public class GradeBook {

    private ArrayList<GradeData> gradeBook;

    public GradeBook() {
        gradeBook = new ArrayList<>();

    }

    public void addGrade(String subject, int grade) {

        for (GradeData g : gradeBook) {
            if (g.getSubject().equals(subject)) {
                System.out.println("Subject already exists");
                return;
            }
        }

        //create new GradeData object
        GradeData newGrade = new GradeData(subject, grade);
        //add it to list
        gradeBook.add(newGrade);

    }

    public void setGrade(String subject, int grade) {
        //search for the subject
        for (GradeData g : gradeBook) {

            if (g.getSubject().equals(subject)) {
                //update the grade
                g.setGrade(grade);
            }
        }
    }
}