Programming Fundamentals

Sequence concerns the order in which code is processed. Of course at the most basic level, code is processed sequentially, in other words it is processed line by line top down from beginning to end. For example a pseudo code version of a simple Hello World program might look something like this -

Begin program
Print "Hello World"
End program

Another version, which would work just as well as the one above, is this -

Begin Program
Call Subroutine PrintMessage
End Program

Subroutine PrintMessage
Print "Hello World"
End Subroutine

In this program there are two sections, a main body and something called a subroutine. In the main body, which in this pseudo code appears before the subroutine, the first and last lines are the same as in the first example and simply begin and end the program. The middle line of the main program calls the subroutine, a term which commonly refers to one or more lines of code which are grouped together in a program using a unique name, so in this example the subroutine is called PrintMessage.

under construction!

under construction!

In 18 years the only programs I've encountered which have never had to be modified are the smallest data update programs. Everything else has either has bug fixes or modifications applied. In other words, anything more than a small one-off program will be changed, and almost certainly by more than one person which means some poor sucker has change your code.

What this means is that in almost every case it is better to design a program so that it is clear and readable for easy modification by other developers than to sacrifice clarity and maintainability in order to optimise performance. Most of the time spent developing a program is done not at the initial development but in modification.

Unfortunately anyone who works as a professional developer sooner or later encounters code written by a show-off. Technically this person is usually very capable and their programs work well, but they may employ seldom-used commands or maybe they just apply their own brand of "logic" to create a solution. Sometimes it's done to optimise performance, other times it just because they've read about something new and they want to use it. It wouldn't be so bad if they used comments to explain what they were doing, but that would be too easy wouldn't it? Best of all, more often than not by the time you get to update the code the author has long since disappeared to pastures new.

So remember, someone else is going to have to update or fix your code so make sure they're going to be able to understand it. Put in plenty of comments, especially around the more complex areas of code.