Book Image

Learn C Programming

By : Jeff Szuhay
Book Image

Learn C Programming

By: Jeff Szuhay

Overview of this book

C is a powerful general-purpose programming language that is excellent for beginners to learn. This book will introduce you to computer programming and software development using C. If you're an experienced developer, this book will help you to become familiar with the C programming language. This C programming book takes you through basic programming concepts and shows you how to implement them in C. Throughout the book, you'll create and run programs that make use of one or more C concepts, such as program structure with functions, data types, and conditional statements. You'll also see how to use looping and iteration, arrays, pointers, and strings. As you make progress, you'll cover code documentation, testing and validation methods, basic input/output, and how to write complete programs in C. By the end of the book, you'll have developed basic programming skills in C, that you can apply to other programming languages and will develop a solid foundation for you to advance as a programmer.
Table of Contents (33 chapters)
Section 1: C Fundamentals
Section 2: Complex Data Types
Section 3: Memory Manipulation
Section 4: Input and Output
Section 5: Building Blocks for Larger Programs

Writing comments to clarify the program later

A lot about writing good code is writing code in a consistent manner. Consistency makes it somewhat easier for the reader (or you) to comprehend at a later time. Consistency is most often a good thing. However, there may be times where we need to step out of that consistency, and for some goodreason, when we write code, that code is particularly twisted or obtuse and difficult to understand. Or, we might write code a certain way that may not be obvious or may not be expected, again for good reason. It is in these circumstances we should comment on our code – not for the compiler, but for ourselves and for others who may be reading our code at a later date, scratching our/their foreheads thinking, "What? What did I/they intend to do here?"

Code comments are the way to provide an explanation of why a particular piece of code is written in a certain way. Let's explore some of the different ways we can write code comments in C.

Comments in code, when done correctly, are ignored by the compiler. They are only for human edification. Consider the following code comments:

/* (1) A single-line C-style comment. */

/* (2) A multi-line
C-style comment. */

* (3) A very common way to
* format a multi-line
* C-Style comment.

/* (4) C-style comments can appear almost anywhere. */

/*(5)*/ printf( /* Say hello. */ "Hello, world!\n" );

/*(6)*/ printf( "Hello, world!\n" ); /* Yay! */

// (7) A C++ style comment (terminated by End-of-Line).

printf( "Hello, world!\n" ); // (8) Say hello; yay!

// (9) A more common way
// of commenting with multi-line
// C++ style comments

// (10) anything can appear after //, even /* ... */ and
// even more // after the first // but they will be
// ignored because they are all in the comment.

The comments illustrated in the preceding code are not particularly useful comments, but they show various ways comments in C can be employed.

Comments with tags (1)(6) are old-style C comments. The rules for these are simple – when a /* is encountered, it is a comment until a */ is subsequently encountered, whether it appears on the same line or several lines later. / * (with a space between them) and * / (with a space between them) are not valid comment indicators.

C comments that have been adopted from C++ are shown with tags (7) through (10). When a // is encountered, it is a comment until an End Of Line (EOL) is encountered. Therefore, these comments cannot appear anywhere like C comments can. Likewise, / / (with a space between them) is not a valid comment indicator.

C comments are more flexible, while C++ style comments are more obvious. Both styles are useful. We'll use both throughout this book.