iOS App Development Portable Genius

Understanding the C Language

C is an old-fashioned programming language that is closely modeled on computer hardware. To use C successfully, you must know a little about how computers work.

This chapter isn’t a complete introduction to C. It’s a simple primer that introduces many key features and gives you enough detail to understand the many more comprehensive tutorials you can find online. It takes most developers a few weeks to master the essentials of programming, and months or even years to become effortlessly fluent.

Understanding computers

A computer is a machine that stores and processes binary patterns. All the numbers, letters, images, web pages, sounds, and other information you work with (or play with) are represented by collections of binary digits (bits), each of which holds a single 1 or 0.

You can’t do much with a single bit, so bits are grouped together. The most basic grouping is a byte—eight bits in a row. Any group of two more bytes in a row is called a word, as shown in Figure 5.3. Different computer systems use different word lengths. In iOS, words are 32-bits long.

5.3 Bits, bytes, and words—the most basic binary groupings.

In computer jargon, a word ...