Writing Code Badly

Good vs. bad code

As every developer knows, it seems a lot easier to write bad code than to engineer good code. We can define good code as being easy to understand and safe to change. Bad code is therefore the opposite of this, where it is very difficult to read the code and understand what problem it is supposed to be solving. We fear changing bad code—we know that we are likely to break something.

Author’s experience: coding nightmare

My own troubles with bad code go all the way back to my first program of note. This was a program written for a school competition, which aimed to assist realtors in helping their customers find the perfect house. Written on the 8-bit Research Machines 380Z computer at school, this was 1981’s answer to Rightmove.

In those pre-web days, it existed as a simple desktop application with a green-screen text-based user interface. It did not have to handle millions, never mind billions, of users. Nor did it have to handle millions of houses. It didn’t even have a nice user interface.

As a piece of code, it was a couple of thousand lines of Microsoft Disk BASIC 9 code. There was no code structure to speak of, just thousands of lines filled with uneven line numbers and cluttered with global variables. To add an even greater element of challenge, BASIC limited every variable to a two-letter name. This made every name in the code utterly incomprehensible. The source code was intentionally written to have as few spaces in it as possible in order to save memory. When you only had 32KB of RAM to fit all of the program code, the data, and the operating system in, every byte mattered.

The program only offered its users basic features. The user interface was of its time, using only text-based forms. It predated graphical operating systems by a decade. The program also had to implement its own data storage system, using files on 5.25-inch floppy disks. Again, affordable database components were of the future. The main feature of the program in question was that users could search for houses within certain price ranges and feature sets. They could filter by terms such as the number of bedrooms or price range.

However, the code itself really was a mess. See for yourself—here’s a photograph of the original listing: