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

Creating a template program to process filenames given on the command line

We begin creating our data file creation program by handling command-line arguments.

In the last chapter, we created a program that expected two filenames on the command line, which were presented via argv; the input file was the first argument and the output file was the second argument. What if we wanted to permit either argument to be omitted? We could no longer rely on argument positioning; we need a way to further identify which argument is input and which argument is output.

To do that, we will revisit the built-in command-line facility getopt(). This facility is older and simpler than getopt_long(), which we demonstrated in Chapter 20, Getting Input from the Command Line. We will specify two options, -i <input filename> and -o <output filename>, neither of which will be required. getopt() does not have the concept of required or optional arguments so we'll have to...