EE150 - Fall 1996

C Programming
Style Guidelines

Introduction

One question that comes up every semester is: Must the programs we write look like the programs in the course textbook? That is, do we have to indent programs in the same way, use the same long variable names, and so on?

The short answer is: Yes!

The longer answer, however, is, well, not exactly.

The basic rule is that your programs must be easy to read. Things like consistent indentation make programs easier to read. If you indent like we do (and, in general, layout your programs like we do), you'll find your programs are as easy to read as ours. However, we realize that not everyone has the same sense of aesthetics as we do. So, we are not fascists about how our programs look, but we are picky. If we get confused in trying to understand your programs, we're going to take off points (and your program grade is based in part on how readable your programs are).

Some Guidelines

Here are some of the guidelines we use in determining how to grade your program for "readability":

• Most importantly - comment your programs. A comment shoudl be in place for every function explaining it's purpose and use. Strange bits of code deserve a comment as well. Variables name comments/descriptions are helpful. On the other hand, you MUST try to not clutter your programs excessively - place your comments consistently and carefully. Make sure they are readable in terms of spacing and english usage.
• The indentation must be consistent. The textbook programs are consistent. But code like this is not:

    z = 10;
  y = 15;
      x = y + z;
  

• You should indent complex constructs like while and for loops. There are a variety of schemes for indenting. The textbook's scheme is fine, as is this one,

  i = 0;
  while (i < N) {
    printf("%i\n", i);
    i = i + 1;
  }
  

  and this one,

  i = 0;
  while (i < N)
    {
      printf("%i\n", i);
      i = i + 1;
    }
  

  Of course, you can feel to use more than two spaces if you like.

• When a statement is too long to fit on a line, you should break up at punctuation characters. For example, you can break up a long printf like this:

  printf(".....formatting string......",
         variable-1, variable-2)
  

  or like this:

  printf(".....formatting string......",
         variable-1,
         variable-2)
  

  Again, here you have to use your judgement.

• It's helpful to have blank lines separating different parts of your program, just to break up the instructions on the page. Our tendency is to stick blank lines between each group of related statements. But at a minimum you want blank lines before the start of each function definition (like before main) and between the variable declarations and the statements.

• Variable names should reflect their usage. If you can't look at a variable and figure out what it's used for, you need a new name. A name like discount_price is fine, dp is not.

Your goal should be to avoid the mistakes shown above. If you do, you are likely to get full credit.

One last thing. This style guide will be expanded as we show more and more C constructs, so you might want to check back here before starting each assignment to see what we have added.