INTRODUCTION

Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the universe trying to build bigger and better idiots. So far the universe is winning.

—RICK COOK

With modern development tools, it's easy to sit down at the keyboard and bang out a working program with no previous design or planning, and that's fine under some circumstances. My VB Helper (www.vb-helper.com) and C# Helper (www.csharphelper.com) websites contain thousands of example programs written in Visual Basic and C#, respectively, and built using exactly that approach. I had an idea (or someone asked me a question) and I pounded out a quick example.

Those types of programs are fine if you're the only one using them and then for only a short while. They're also okay if, as on my websites, they're intended only to demonstrate a programming technique and they never leave the confines of the programming laboratory.

If this kind of slap-dash program escapes into the wild, however, the result can be disastrous. At best, nonprogrammers who use these programs quickly become confused. At worst, they can wreak havoc on their computers and even on those of their friends and coworkers.

Even experienced developers sometimes run afoul of these half-baked programs. I know someone (I won't give names, but I also won't say it wasn't me) who wrote a simple recursive script to delete the files in a directory hierarchy. Unfortunately, the script recursively climbed ...

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