*destination++ = *source++

*destination = *source; destination++; source++;

For much of the book, Oualline gives examples of good and bad code, and summarizes with style rules. His rules are simple and easy to apply. Some of the rules apply to the process of writing code. For example, "Comment your code as you write it." (This rule, he says, saves time in the long run.) Other rules address the code itself: "Constant names are all upper case" and "Follow every variable declaration with a comment that defines it." Some rules just make a programmer's life easier: "Assume that *,/, and % come before + and -. Put parentheses around everything else."

The style rules are aimed at making programs readable and reliable. Good variable and subroutine names, which help make the code explain itself, and good comments, which help reveal the organization of programs, enhance readability. Oualline strives to increase reliability by limiting the code to safe subsets of the C language. (Not allowing shortcuts such as *destination++ = *source++ reduces the risk of problematic side effects.) Oualline describes this emphasis on readable and reliable code as "defensive programming" or "doing a lot of thinking so I don't have to do a lot of thinking."

The chapter on makefile style is outstanding and to my knowledge unique. Makefiles are essential to C programming and are often the hardest part of a project to understand. Other books describe how to use makefiles, but this is the only book I have seen that tells how to organize and format them. Oualline formally defines many makefile items that have become pseudo standards over the years. This material may seem trivial to an experienced UNIX C programmer, but many C programmers today have never worked on a UNIX system (believe it or not).

The chapter on user-friendly programming is a bit out of place, but useful. It discusses how to write programs that users will actually use. (It includes the Law of Least Astonishment: The program should act in a way that least astonishes the user.)

The style manual is 35 pages of rules without all the discussion. For those short on time, this book-within-a-book provides a concise summary of the text.

The first appendix shows three complete code examples (two in C, one in C++) that employ the style rules given in the body of the book. These examples show Oualline's recommendations in practice. The second appendix lists all the rules given in the chapters. (Take these seven pages and pin them on the wall next to the coffee machine.)

C Elements of Style is a deserving addition to the desk top — not just the bookshelf.

References