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

Understanding the void* type

There are times when the type of a pointer is not known. This occurs primarily in C library functions.

For this reason, the void* pointer type represents a generic, as yet unspecified pointer; in other words, a pointer whose type is not known at declaration. Any pointer type can be assigned to a pointer variable of the void* type. However, before that pointer variable can be accessed, the type of the data being accessed must be specified through the use of a casting operation:

void* aPtr = NULL;  // we don't yet know what it points to.
aPtr = &height; // it has the address of height, but no type yet.
int h = (int)*aPtr; // with casting, we can now go to that address
// and fetch an integer value.

In the first statement of the preceding code block, we see how aPtr is declared as a pointer but we don't yet know it's type or what it points to. In the next statement, aPtr is given the...