Although readers with experience in a variety of languages may be satisfied with a brief explanation and a couple of examples, readers with less experience need more. Side issues that don't belong in the main flow. Some questions raise technical issues that won't be of interest to all readers. Material too advanced or too esoteric to interest the average reader. Common differences among C compilers.
Warnings alert readers to common pitfalls.
Although many of these are pointers to topics covered later in the book, some point to previous topics that the reader may wish to review. Sidebars cover topics that aren't strictly part of C but that every knowledgeable C programmer should be aware of, including unsigned integers, the IEEE floating-point standard, and Unicode. Appendices provide valuable reference information. Programs Choosing illustrative programs isn't an easy job. If programs are too brief and artificial, readers won't get any sense of how the features are used in the real world.