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

Comparing pointers

As we stated earlier, we never concern ourselves about the specific value of a pointer. However, we can carry out comparison operations on pointers for the following:

  • Is a pointer equal or not equal to NULL?
  • Is a pointer equal to or not equal to a named location?
  • Is one pointer equal or not equal to another pointer?

In each case, we can either check for equality (==) or inequality (!=). Because we can never be certain of the variable ordering in memory, it makes no sense whatsoever to test whether one pointer is greater than (>) or less than (<) another pointer.

If we consistently apply the guideline to always assign a value to a pointer, even if that value is NULL, we can then make the following comparisons:

if( pDimension == NULL ) printf( "pDimension points to nothing!\n" );

if( pDimension != NULL ) printf( "pDimension points to something!\n" );

The first...