Working with Data

Most software operates on data. This might be a primary function of your application (e.g. image editor) or a secondary function (e.g. user preferences). As a software developer, you need to give considerable thought to how you will handle user data.

Some examples of data that you might care about:

• The data that the user has captured and wishes to save e.g. an image that they have created in an image-editor, or the text from a note.
• The position and size of the application window, window size, or other settings that you might want to save and restore when the application is relaunched.
• User preferences that they might set in your application e.g. preferred font or font size.
• The public key to connect to a remote machine.
• The software license key for your application.

Operations you may need to do:

• Store data in a file so that you can load and restore it later.
• Transfer the data to another process that can use it, or to a completely different system e.g. over the internet.
• Filter it to a subset of your original data. Sort it. Modify it.

Let’s start by reviewing something we already know - data types.