Student.java

import java.util.ArrayList;

public class Student {
    String name;
    ArrayList<Integer> grades;

    public Student(String name) {
        this.name = name;
        this.grades = new ArrayList<>();
    }

    public double getAverage() {
        int sum = 0;
        for (int grade : grades) {
            sum += grade;
        }
        return grades.size() == 0 ? 0 : (double) sum / grades.size();
    }

    public int getHighest() {
        int max = Integer.MIN_VALUE;
        for (int grade : grades) {
            if (grade > max) {
                max = grade;
            }
        }
        return max;
    }

    public int getLowest() {
        int min = Integer.MAX_VALUE;
        for (int grade : grades) {
            if (grade < min) {
                min = grade;
            }
        }
        return min;
    }
}