When you start out writing programs, each program might seem like an entirely separate project, designed and constructed from scratch. However, this is not a prudent way to create computer programs, and it's not the way most programs are created today.
There is a much better alternative—reuse of pre-constructed and pre-tested programs or parts of programs.
A high degree of reuse means far less code to write and allows you to tap into well-designed, well-tested software components written by highly skilled experts.
Even the simplest C# programs, including the first few you will encounter in this book, rely on software reuse under ...