C# 24-Hour Trainer, 2nd Edition

Section V

System Interactions

The lessons up to this point have explained how you can do some pretty remarkable things. Using their techniques you can read inputs entered by the user, perform intricate calculations, repeat a sequence of commands a huge number of times, and even build your own classes to model complex situations.

All of the programs that you've written so far, however, are self-contained. They get input from the user, but otherwise they don't interact with the computer.

The lessons in this section explain some of the ways a program can interact with the system. They explain how to read and write files, explore the filesystem, and print.

• Lesson 29: Using Files
• Lesson 30: Printing

NOTE

A program can interact with the computer in lots of other ways. It can interact with hardware through serial ports and special devices and connect to websites or other programs over a network. It can use copy-and-paste and the clipboard to interact with other programs. It even has many different ways to interact with the same part of the system. For example, a program has many ways to manipulate files, read and modify the Windows registry, and save and restore program parameters. The lessons in this part of the book describe some of the ways a program can interact with the wider system, but these are by no means the only ways.