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Introduction to Computers and Programming Language
2006 Pearson Education, Inc. All rights reserved.

OBJECTIVES
In this chapter you will learn: Basic hardware and software concepts. The different types of programming languages. Which programming languages are most widely used. A typical C++ program development environment. The history of the industry-standard object-oriented system modeling language, the UML. The history of the Internet and the World Wide Web. To test-drive C++ applications in most popular C++ environmentsGNU C++ running on Linux

2006 Pearson Education, Inc. All rights reserved.

1.1 Introduction
Software
Instructions to command computer to perform actions and make decisions

Hardware Standardized version of C++

United States
American National Standards Institute (ANSI)

Worldwide
International Organization for Standardization (ISO)

Structured programming Object-oriented programming

2006 Pearson Education, Inc. All rights reserved.

1.2 What Is a Computer?

Computer
Device capable of performing computations and making logical decisions

Computer programs
Sets of instructions that control computers processing of data Written by people called computer programmers

Hardware
Various devices comprising computer
Keyboard, screen, mouse, disks, memory, CD-ROM, processing units, etc.

2006 Pearson Education, Inc. All rights reserved.

1.3 Computer Organization

Six logical units of computer
Input unit
Receiving section Obtains information from input devices Keyboard, mouse, microphone, scanner, networks, etc.

Output unit
Shipping section Places information processed by computer on output devices Screen, printer, networks, etc. Information can also be used to control other devices

2006 Pearson Education, Inc. All rights reserved.

1.3 Computer Organization (Cont.)

Six logical units of computer (Cont.)
Memory unit
Rapid access, relatively low capacity warehouse section Retains information from input unit Immediately available for processing Retains processed information Until placed on output devices Often called memory or primary memory

Arithmetic and logic unit (ALU)

Manufacturing section

Performs arithmetic calculations and logic decisions

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PC and its component

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PC and its component

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Midrange Server and its component

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Motherboard and Other Component

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1.3 Computer Organization (Cont.)

Six logical units of computer (Cont.)
Central processing unit (CPU)
Administrative section Coordinates and supervises other sections of computer

Secondary storage unit

Long-term, high-capacity warehouse section Stores inactive programs or data Secondary storage devices Hard drives, CDs, DVDs Slower to access than primary memory Less expensive per unit than primary memory

2006 Pearson Education, Inc. All rights reserved.

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1.4 Early Operating Systems

What is an OS
Operating systems are software systems that make using computers more convenient for users, application developers and system administrators. Operating systems provide services that allow each application to execute safely, efficiently and concurrently (i.e., in parallel) with other applications. The software that contains the core components of the operating system is called the kernel. Popular desktop operating systems include Linux, Windows and MacOS X. Popular mobile operating systems used in smartphones and tablets include Googles Android, BlackBerry OS and Apples iOS (for its iPhone, iPad and iPod Touch devices).

2006 Pearson Education, Inc. All rights reserved.

Desktop and Mobile Operating System

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1.5 What does an OS Do

Process Management

A process is an executing program. It has its code, data, a certain set of resources allowed to it, and one or more flows of execution through the code. The OS manages the allocation of resources to these processes, and also provides system calls to manage these processes. Examples Scheduling processing within the cpu
Multi Tasking (jumping between processing jobs) Handles input and outputs

2006 Pearson Education, Inc. All rights reserved.

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1.5 What does an OS Do

Memory Management

Memory must be shared between the OS and an application program. The OS must manage the allocation of memory to processes and control the memory management hardware that determines which memory locations a process may access.
Examples
Managing Cache memory Managing RAM Managing Virtual Memory

2006 Pearson Education, Inc. All rights reserved.

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1.5 What does an OS Do

Device Management

Information is sent through a computers input and output devices. Processes access these devices using the system call interface. The OS tries to manage said devices in a manner that makes them efficiently shared among all processes requiring them. A system call is a programming interface to the services provided by the OS, typically written in C/C++. Examples
Makes sure that the correct drivers are installed so that the computer can communicate with all the input and output devices connected to the machine/computer

2006 Pearson Education, Inc. All rights reserved.

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1.6 Linux Operating System

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1.6 Windows Operating System

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1.6 Mac OS Operating System

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1.7 Machine Languages, Assembly Languages and High-Level Languages Three types of computer languages
Machine language
Only language computer directly understands Natural language of computer Defined by hardware design Generally consist of strings of numbers Ultimately 0s and 1s Instruct computers to perform elementary operations Cumbersome for humans Example +1300042774 +1400593419 +1200274027
2006 Pearson Education, Inc. All rights reserved.

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1.7 Machine Languages, Assembly Languages and High-Level Languages (Cont.) Three types of computer languages (Cont.)
Assembly language
English-like abbreviations representing elementary computer operations Clearer to humans Incomprehensible to computers Convert to machine language by translator programs (assemblers) Example load basepay add overpay store grosspay

2006 Pearson Education, Inc. All rights reserved.

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1.7 Machine Languages, Assembly Languages and High-Level Languages (Cont.)

Three types of computer languages (Cont.)
High-level languages
Similar to everyday English Uses common mathematical notations Single statements accomplish substantial tasks Converted to machine language by translator programs (compilers) Interpreter programs Directly execute high-level language programs Execute more slowly than the compiled program Example grossPay = basePay + overTimePay

2006 Pearson Education, Inc. All rights reserved.

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1.8 History of C and C++

History of C
Evolved from BCPL and B
Developed by Dennis Ritchie (Bell Laboratories)

Development language of UNIX Hardware independent

Can write portable programs

ANSI and ISO standard for C published in 1990

ANSI/ISO 9899: 1990

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1.8 History of C and C++ (Cont.)

History of C++
Extension of C
Developed by Bjarne Stroustrup (Bell Laboratories) in early 1980s

Provides new features to spruce up C Provides capabilities for object-oriented programming

Objects: reusable software components Model items in the real world Object-oriented programs Easier to understand, correct and modify

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1.9 C++ Standard Library

C++ programs
Built from pieces called classes and functions

C++ Standard Library

Rich collections of existing classes and functions
Reusable in new applications

Boost C++ Library

Developed by Open Source Community 100 over libraries

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1.10 History of Java

Java
Originally for intelligent consumer-electronic devices
Designed by Sun Microsystems

Then used for creating Web pages with dynamic content Now also used for:
Develop large-scale enterprise applications Enhance World Wide Web server functionality Provide applications for consumer devices (cell phones, etc.)

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1.11 Typical C++ Development Environment

C++ programs normally undergo six phases
Edit
Programmer writes program (and stores source code on disk)

Preprocess
Perform certain manipulations before compilation

Compile
Compiler translates C++ programs into machine languages

Link
Link object code with missing functions and data

Load
Transfer executable image to memory

Execute
Execute the program one instruction at a time
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Fig. 1.1 | Typical C++ environment.

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1.11 Typical C++ Development Environment (Cont.)

Input/output
cin
Standard input stream Normally inputs from keyboard

cout
Standard output stream Normally outputs to computer screen

cerr
Standard error stream Displays error messages

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1.11 Notes About C++ and C++ How to Program, 5/e

This book is geared toward novice programmers
Stresses programming clarity

Portability
C and C++ programs can run on many different computers

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1.11 Test-Driving a C++ Application

Running and interacting with a C++ application
Windows XP Command Prompt
Linux shell

2006 Pearson Education, Inc. All rights reserved.