10 May, 2009 Leave a comment
I was in a shop recently and I bought 6 items at £5 each. A total price of £30, even I can manage that mental arithmetic without resorting to a calculator. However, the till decided that the total price was £30.01. For a penny I really can’t be bothered to argue, but it got me thinking about code quality and wondering about what awfulness must be sitting in that system to create such a simple basic mistake.
My colleagues are probably all aware of my views on code quality. I rant daily whenever I see examples on ineptitude by people that are paid money to write code. I read and respond on forums in order to help others learn their craft, or just get unstuck when they accidentally dig themselves in a hole. However, I see on an almost daily basis these days people posting their homework questions with no apparent attempt to at least try to work it out from themselves.
Take this example I found on Code Project a while ago:
I need to know how to do some simple things with arrays please help with any!
1.Find largest or smallest value
2.Count how many times a given value is in the array
3.Count the number of even or odd integers in the array
4.Add up the sum and compute the mean
5.Create another array of the same size containing the same values in reverse order
This is very obviously an exercise from an introductory course on the language they were studying. They just want someone to give them an answer that they can copy and paste. If this is what they are like now, imagine what they will be like years down the road writing commercial software.
I’ve seen lots of evidence over the years of people writing software by copy and pasting examples from the internet without thought of what is actually going on. This results in slow, bloated, inefficient code that is integrated very badly with the rest of the system, hard to read, hard to debug, and is just generally a complete mess.
If you are tempted to copy and paste some code snippet from the internet for your application then stop and think first. Do you actually understand the code? If not, then don’t copy and paste it. If you don’t understand it, how will you debug it?
I would say that if you are tempted to copy and paste from the internet that you create a very small test application first, paste it in to that and learn how it works. Once you understand how it all fits together and how it works you can then write a version that will integrate in to your application.
While you are at it, write some unit tests to go with it. Make sure you test for edge cases, make sure you test for some normal cases too. If you ever get a bug, then add a test that replicates the bug. So if someone suddenly discovers your software things that 5 times 6 equals 30.01 you can add a test for it, fix the bug and redeploy the system. Hopefully, this would have been caught before the public get a chance to see the glaring error and write blog posts about it.