14 09 Projet

This lesson puts everything we have learned about files into practice with a small project. The goal is to list students grouped by field of study and persist the whole thing in a single text file. We will build two simple classes and then orchestrate them from main.

The first class is Student. It carries an id, a name and a field id. The student id is incremented automatically through a static counter, and the field id is filled in later, when each student is attached to a field. The second class is Field (the academic track), which exposes its own auto-incremented id and a name.

Building the data in main

• Declare an array of three Field instances representing the available tracks.
• Declare an array of five Student instances.
• Assign each student to one of the fields so the link is materialized.
• Create the destination text file using FileWriter as in the previous lesson.
• Write the fields and the students one after the other so the file groups them together.

By the end of the video you have a working mini-application that builds objects in memory, ties them together and writes their content to disk. This is also a good moment to revisit object-oriented basics: each entity is a class with its own state, and the file is the persistent representation of that state. The next lesson reads the same file back to display the data.