Programacion

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CHAPTER 1
Introduction to Programming and the
Java Language

CHAPTER CONTENTS
Introduction
1.1 Basic Computer Concepts
1.1.1 Hardware
1.1.2 Operating Systems
1.1.3 Application Software
1.1.4 Computer Networks and the Internet
1.2 Practice Activity: Displaying System Configuration
1.2.1 Displaying Windows ConfigurationInformation
1.2.2 Displaying Unix/Linux Configuration Information
1.3 Data Representation
1.3.1 Binary Numbers
1.3.2 Using Hexadecimal Numbers to
Represent Binary Numbers
1.3.3 Representing Characters with the
Unicode Character Set

1.4 Programming Languages
1.4.1 High- and Low-Level Languages
1.4.2 An Introduction to ObjectOriented Programming
1.4.3 The Java Language
1.5 An Introduction toProgramming
1.5.1 Programming Basics
1.5.2 Program Design with Pseudocode
1.5.3 Developing a Java Application
1.5.4 Programming Activity 1: Writing
a First Java Application
1.6 Chapter Summary
1.7 Exercises, Problems, and Projects
1.7.1 Multiple Choice Exercises
1.7.2 Converting Numbers
1.7.3 General Questions
1.7.4 Technical Writing
1.7.5 Group Project

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Introduction to Programming and the Java Language

Introduction
Computer applications touch almost every aspect of our lives. They run
automated teller machines, the grocery store’s checkout register, the
appointment calendar at your doctor’s office, airport kiosks for flight
check-in, a restaurant’s meal-ordering system, and online auctions,just to
name a few applications. On your personal computer, you may run a word
processor, virus detection software, a spreadsheet, computer games, and an
image processing system.
Someone, usually a team of programmers, wrote those applications. If
you’re reading this book, you’re probably curious about what’s involved in
writing applications, and you would like to write a few yourself.Perhaps
you have an idea for the world’s next great application or computer game.
In this book, we’ll cover the basics of writing applications. Specifically, we’ll
use the Java programming language. Keep in mind, however, that becoming
a good programmer requires more than mastering the rules, or syntax, of a
programming language. You also must master basic programming techniques. These areestablished methods for performing common programming operations, such as calculating a total, finding an average, or
arranging a group of items in order.
You also must master good software engineering principles, so that you
design code that is readable, easily maintained, and reusable. By readable,
we mean that someone else should be able to read your program and figure
out what it does and how itdoes it. Writing readable code is especially
important for programmers who want to advance in their careers, because
it allows someone else to take over the maintenance of your program while
you move on to bigger and better responsibilities. Ease of maintenance is
also an important aspect of programming, because the specifications for
any program are continually changing. How many programscan you name
that have had only one version? Not many. Well-designed code allows you
and others to incorporate prewritten and pretested modules into your program, thus reducing the time to develop a program and yielding code that
is more robust and has fewer bugs. One useful feature of the Java programming language is the large supply of prewritten code that you are free to use
in yourprograms.
Programming is an exciting activity. It’s very satisfying to decompose a
complex task into computer instructions and watch your program come

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1.1 Basic Computer Concepts

alive. It can be frustrating, however, when your program either doesn’t run
at all or produces the wrong output.
Writing correct programs is critical....