Transcript Internet and World Wide Web How to Program

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Chapter 1 – Introduction to
Computers, the Internet and the Web
Outline
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
1.11
1.12
1.13
1.14
1.15
Introduction
The Future of Computing
e-Business and e-Commerce
What is a Computer?
Types of Programming Languages
Other High-Level Languages
Structured Programming
History of the Internet
Personal Computing, Distributed Computing and
Client/Server Computing
History of the World Wide Web
Hardware Trends
The Key Software Trend: Object Technology
JavaScript: Object-Based Scripting for the Web
Browser Portability
Evolution of the How to Program Series: C and C++
 2001 Deitel & Associates, Inc. All rights reserved.
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Chapter 1 – Introduction to
Computers, the Internet and the Web
Outline
1.16
1.17
1.18
1.19
Java and Java How to Program
Internet and World Wide Web How to Program
e-Business and e-Commerce How to Program
Dynamic HTML
 2001 Deitel & Associates, Inc. All rights reserved.
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1.1 Introduction
• We will learn
– Structured programming and proper programming
techniques
• This course is appropriate for
– Novices with little or no programming experience
– Experienced professionals building substantial
information systems
 2001 Deitel & Associates, Inc. All rights reserved.
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1.2 The Future of Computing
• Future of Computers
– Use increasing dramatically
– Costs decreasing
– Explosion of Internet and World Wide Web
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Multimedia content
Increasing bandwidth
Magazines and books already going online
Easy international communication
– Could replace TV, radio and phone
– Helping the disabled
 2001 Deitel & Associates, Inc. All rights reserved.
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1.3 e-Business and e-Commerce
• e-Business
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Provides products and services 24 hours a day
Provides unlimited inventory
Allows consumer to comparison shop
Essential to business success
Replacing “brick and mortar” stores
Personalize user’s experience
• New business models introduced by Web
– eBay
• Online auctions
– Priceline.com
• Customers name own price
 2001 Deitel & Associates, Inc. All rights reserved.
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1.3 e-Business and e-Commerce
• Consequences of Internet and Web
– Privacy invasion
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One of the risks of Internet
Personal information on the Web
Tracking of Web movement
Credit card security
– Piracy of intellectual property
• Copyright infringement
• MP3
 2001 Deitel & Associates, Inc. All rights reserved.
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1.4 What is a Computer?
• Computer
– Device capable of performing computations and
making logical decisions
– Computers process data under the control of sets of
instructions called computer programs
• Hardware
– Various devices comprising a computer
– Keyboard, screen, mouse, disks, memory, CD-ROM,
and processing units
• Software
– Programs that run on a computer
 2001 Deitel & Associates, Inc. All rights reserved.
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1.5 Types of Programming Languages
• Three types of programming languages
1. Machine languages
• Strings of numbers giving machine specific instructions
• Example:
+1300042774
+1400593419
+1200274027
2. Assembly languages
• English-like abbreviations representing elementary computer
operations (translated via assemblers)
• Example:
LOAD
BASEPAY
ADD
OVERPAY
STORE GROSSPAY
 2001 Deitel & Associates, Inc. All rights reserved.
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1.5 Types of Programming Languages
3. High-level languages
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Codes similar to everyday English
Use mathematical notations (translated via compilers)
Example:
grossPay = basePay + overTimePay
 2001 Deitel & Associates, Inc. All rights reserved.
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1.6 Other High-level Languages
• Other high-level languages
– FORTRAN
• Used for scientific and engineering applications
– COBOL
• Used to manipulate large amounts of data
– Pascal
• Intended for academic use
 2001 Deitel & Associates, Inc. All rights reserved.
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1.7 Structured Programming
• Structured programming
– Disciplined approach to writing programs
– Clear, easy to test and debug and easy to modify
• Multitasking
– Specifying that many activities run in parallel
 2001 Deitel & Associates, Inc. All rights reserved.
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1.8 History of the Internet
• The Internet enables
– Quick and easy communication via e-mail
– International networking of computers
• Packet switching
– The transfer of digital data via small packets
– Allows multiple users to send and receive data
simultaneously
• No centralized control
– If one part of the Internet fails, other parts can still
operate
• Bandwidth
– Information carrying capacity of communications lines
 2001 Deitel & Associates, Inc. All rights reserved.
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1.9 Personal Computing, Distributed
Computing, and Client/Server Computing
• Personal computers
– Economical enough for individual
• Distributed computing
– Computing distributed over networks
• Client/server computing
– Sharing of information across computer networks
between file servers and clients (personal computers)
 2001 Deitel & Associates, Inc. All rights reserved.
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1.10 History of the World Wide Web
• WWW
– Allows computer users to locate and view multimediabased documents
– Introduced in 1990 by Tim Berners-Lee
• Internet today
– Mixes computing and communications technologies
– Makes information constantly and instantly available to
anyone with a connection
 2001 Deitel & Associates, Inc. All rights reserved.
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1.11 Hardware Trends
• Improving technologies
– Internet community thrives on improvements of
• Hardware
• Software
• Communications
– Cost of products and services
• Consistently dropping over the decades
– Computer capacity and speed
• Doubles every two years (on average)
– Microprocessor chip
• Laid groundwork in late 1970s and 1980s for productivity
improvements of the 1990s
 2001 Deitel & Associates, Inc. All rights reserved.
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1.12 The Key Software Trend: Object
Technology
• Objects
– Reusable software components that model items in the
real world
– Meaningful software units
• Date objects, time objects, paycheck objects, invoice objects,
audio objects, video objects, file objects, record objects, etc.
• Any noun can be represented as an object
– More understandable, better organized, and easier to
maintain than procedural programming
– Favor modularity
 2001 Deitel & Associates, Inc. All rights reserved.
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1.13 JavaScript: Object-Based
Scripting for the Web
• JavaScript
– Attractive package for advancing level of programming
language education
– Object-based language
– Supports proper software engineering techniques
– Free for download in today’s most popular Web
browsers
• Attractive to colleges
• Bug fixes and new versions easily obtained
– Powerful scripting language
• Portable
• Programs execute interpretively on client machines
 2001 Deitel & Associates, Inc. All rights reserved.
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1.14 Browser Portability
• Browser portability
– Great challenge
• Great diversity of client browsers in use
• Many different platforms also in use
• Difficult to
– Know capabilities and features of all browsers and
platforms in use
– Find correct mix between absolute portability,
complexity and usability of features
 2001 Deitel & Associates, Inc. All rights reserved.
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1.15 Evolution of the How to Program
Series: C++ and C++
• C
– Wasn’t used for teaching because of Pascal
• Used in business and in operating systems
• C How to Program began teaching C to university students
– Portable across many platforms
• C++
– Extension of C
– Provides capabilities for object-oriented programming
– Very widely used in industry
• Lead to writing of C++ How to Program
 2001 Deitel & Associates, Inc. All rights reserved.
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1.16 Java and Java How to Program
• Java is used to
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Create Web pages with dynamic and interactive content
Develop large-scale enterprise applications
Enhance the functionality of Web servers
Provide applications for consumer devices (such as cell
phones, pagers and personal digital assistants)
• Java How to Program
– Closely followed the development of Java by Sun
– Teaches first-year programming students the essentials
of graphics, images, animation, audio, video, database,
networking, multithreading and collaborative
computing
 2001 Deitel & Associates, Inc. All rights reserved.
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1.17 Internet and World Wide Web
How to Program
• Internet and World Wide Web How to Program
– Followed the Internet boom
– Focuses on enhanced capabilities of the Web
• Still provides a solid treatment of programming principles
 2001 Deitel & Associates, Inc. All rights reserved.
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1.18 e-Business and e-Commerce
How to Program
• e-Business and e-Commerce How to Program:
– Step beyond Internet and World Wide Web How to
Program
– Explicitly teaches programming for e-Business and ecommerce
– Firm grounding for conducting business on-line
– Computer programming and basic principles of
computer science
– JavaScript primary programming language
 2001 Deitel & Associates, Inc. All rights reserved.
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1.19 Dynamic HTML
• DHTML
– Two versions
• Microsoft
• Netscape
– Consists of number of technologies freely available for
download
– Used for developing high-performance, Web-based
applications
• Much of application’s work performed directly on client rather
then on server or Internet
 2001 Deitel & Associates, Inc. All rights reserved.