Every programming book starts with a “Hello World!” example. It’s the most basic program you can write in any language and I use it or its many variations (“Goodbye Cruel World!”) to make sure my development environment is set up properly. This site houses Hello World! examples for dozens of programming languages including C++, Perl, Visual Basic and tons I’ve never even heard of.
My favorite is the Hello World! for Microsoft Visual C++, which checks in at almost 400 lines of code!