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

Opening and closing a file

To create a stream, a filename, described in the following section, and an I/O mode must be specified.

There are three general I/O modes that are specified with character strings, as follows:

  • r: Opens an existing file for reading. It fails if the filename does not exist.
  • w: Opens a file for writing. If the file exists, existing data is lost; otherwise, the file is created.
  • a: Opens a file for appending. If the file exists, writing commences at the end of the file; otherwise, the file is created.

These are all one-way modes. That is, a file opened for reading with r can only be read; it cannot be updated. Two-way modes exist by appending + to each of the preceding modes—for example, r+, w+, and a+. When files are opened for reading and writing, care must be exercised to re-position the current file position so as not to inadvertently overwrite existing data. We will look at the file...