Project: A Console Grade Book

This project combines classes, collections, loops, exceptions and formatted output into one practical program.

Design

Create a Student class with a name and a list of scores. A GradeBook class holds students and provides addStudent and printReport methods.

Build the Classes

Keep input and output in main. The model classes should not print anything themselves, which makes them easier to reuse and test.

import java.util.ArrayList;
import java.util.List;

class Student {
    private final String name;
    private final List<Integer> scores = new ArrayList<>();

    Student(String name) {
        this.name = name;
    }

    void addScore(int score) {
        if (score < 0 || score > 100) {
            throw new IllegalArgumentException("Score must be 0 to 100");
        }
        scores.add(score);
    }

    double average() {
        if (scores.isEmpty()) return 0;
        int total = 0;
        for (int score : scores) total += score;
        return (double) total / scores.size();
    }

    String name() { return name; }
}

Report

Sort students by average before printing. Use String.format to align the columns so the output is readable.

students.sort((a, b) -> Double.compare(b.average(), a.average()));

for (Student student : students) {
    System.out.printf("%-20s %6.1f%n", student.name(), student.average());
}

Practice

1. Add a method that returns the highest score for a student.
2. Add a subject field to Student.
3. Print a class average at the end of the report.

Hands-on exercise

Build the GradeBook project.
1. Add at least four students with two or three scores each.
2. Reject scores outside 0 to 100.
3. Print a report sorted by average, highest first.
4. Include a class average at the bottom.

Recap

A small application is a set of focused classes plus a thin main method that connects input, logic and output.