Beginning C: From Novice to Professional, Fourth Edition

APPENDIX AComputer Arithmetic

In the chapters of this book, I've deliberately kept discussion of arithmetic to a minimum. However, it's important, so I'm going to quickly go over the subject in this appendix. If you feel confident in your math skills, this review will be old hat to you. If you find the math parts tough, this section should show you how easy it really is.

Binary Numbers

First, let's consider exactly what you intend when you write a common, everyday decimal number such as 324 or 911. Obviously what you mean is three hundred and twenty-four or nine hundred and eleven. Put more precisely, you mean the following:

324 is 3 × 102 + 2 × 101 + 4 × 100, which is 3 × 10 × 10 + 2 × 10 + 4

911 is 9 × 102 + 1 × 101 + 1 × 100, which is 9 ...