Chapter 1: How a C Program Works

Overview

You probably interact with computer programs many times during an average day. When you arrive at work and find out your computer doesn t work, you call tech support. At the other end of the telephone line, a computer program forces you to navigate a voicemail menu maze and then tortures you while you are on perpetual hold with repeated insincere messages about how important your call is, along with false promises about how soon you will get through.

When you re finally done with tech support, you decide to take a break and log on to your now-working computer to do battle with giant alien insects from the planet Megazoid. Unfortunately , the network administrator catches you goofing off using yet another computer program which monitors employee computer usage. Assuming you are still employed, an accounts payable program then generates your payroll check.

On your way home, you decide you need some cash and stop at an ATM, where a computer program confirms (hopefully) you have enough money in your bank account and then instructs the machine to dispense the requested cash and (unfortunately) deducts that same amount from your account.

Most people, when they interact with computers as part of their daily routine, don t need to consider what a computer program is or how it works. However, a computer programmer should know the answers to these and related questions, such as what is a programming language, and how does a C++ program actually work? When you have completed this chapter, you will know the answers to these questions, and also understand how to create and run your own computer program.