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

Printing optimal field widths for doubles

The g and G type specifiers behave either like the f type conversion or the e and E type conversions, depending on the value to be converted, as follows:

printf( "Use of the %%g, and %%G format specifiers:\n" );
printf( " Specifier %%18.12 g%%18.3g" );
printf( " %%18.3G %%18g\n" );
double k = aDouble * 1e-15;
for( int i = 0 ; i < 10 ; i++, k *= 1000 )
printf( " [%18.12g][%18.3g][%18.3G][%18g]\n" ,
k , k , k , k );

The value of k is assigned aDouble multiplied by a very small number, giving a very small number. By using a loop and multiplying k by 1,000, various g or G type conversions are used in each iteration as the value increases. We will see that the g or G type conversions attempt to format the value in the shortest format possible for the given value. This will be clear in the program's output.

Enter these code snippets into double.c. Compile and run...