Copy and Paste programming – A bad habit
I usually stay away from religious discussions when it comes to programming habits and technology choices simply because they don’t usually make any sense at all and are most often just based on emotions. Arguing if VB.Net is better or worse than C# is just nonsense in my book since the differences between them are minor. They both target the same platforms, and use the same framework, of course there are differences but none of them are so great that you would say that this is a much better language. I personally think that XML literals in VB are great but that alone doesn’t make VB a better language. It is just easier to handle XML in VB, so if you do a lot of that VB is a better choice for that particular purpose. I also like the ease with which C# handles iterators, but again that doesn’t make C# a better language, it just make that particular code part easier.
Another discussion I often see on the Web is if the Java J2EE framework is better or worse than the .Net framework. Again this just stir up emotions, if you’re a Java programmer you would of course say that Java is better than .Net and the other way around. It’s not true though… Java is not better than .Net and neither is .Net better than Java. It all comes down to which platform you’re targeting and what the requirements are for the project at hand.
Is an axe better than a saw? No, they are both exceptionally bad tools – if you’re trying to nail two pieces of wood together, that is. In that case you should use a hammer and not an axe and definitely not a saw.
Having said that, this post will still be a rant about a thing that really grinds my gears, copy and paste programming.
Why you should ban Copy and Paste
I want to start by making one thing very clear, I do not think it’s a bad habit to copy a great piece of code you find somewhere on the web and then paste it into your project. As long as you test the code and perhaps refactor it to fit your naming convention then that’s just fine. What I talk about is the habit of copying and pasting the same code all around a project or even between different projects. Come on! If you’re reading this blog there’s a big chance that you’re a .Net developer and as such you use a modern OOP language. The whole purpose of object oriented programming is to create classes for code reuse and to preserve encapsulation. Even if you’re using a structured programming language you can still refactor your code so that you don’t have to repeat the same thing over and over.
Even though older code might be well used and therefore perhaps less buggy doesn’t mean that it will stay that way. Business rules changes and if you need to change how a particular piece of code works you should only need to do that in one place. Also, if the code does contain a bug, you have just introduced the same bug in another place. The next time you feel the urge to copy some code think again and cut it instead. Cutting the code and pasting it elsewhere means you’re refactoring your code and refactoring (to paraphrase Martha Stewart) is a good thing. Cut the code, paste it into a new method and call that method from the place the code used to reside.
If you’re working on a WPF or Silverlight project you don’t even have to copy and paste common XAML code, use a ResourceDictionary instead. But that’s design code, it’s much more important to not copy and paste business logic or data access layer code to different places.
What do you mean conclusion?
Haven’t you paid attention?
Stop copy and paste code! :)