Bài 5. Cách thức vận động, phát triển của sự vật và hiện tượng

Chapter 13 Programming Languages and Program Development
Chapter 13 Objectives
Describe various ways to develop Web pages including HTML, scripting languages, DHTML, XML, WML, and Web page authoring software
Differentiate between machine
and assembly languages
Identify and discuss the purpose of
procedural programming languages
Identify and discuss the characteristics of object-oriented programming languages
Discuss the advantages and uses of visual programming languages
Identify the uses of other programming languages and other program development tools
Identify the uses of popular multimedia
authoring programs
List the six steps in the program development cycle
Differentiate between structured design and
object-oriented design
Explain the basic control structures and design tools used in designing solutions to programming problems
Computer Programs and Programming Languages
What is a computer program?
p. 664 Fig. 13-1
Set of instructions that directs computer to perform tasks
Programming language—used to write instructions
Computer Programs and Programming Languages
What are low-level languages and high-level languages?
p. 665
High-level
language
Low-level
language
Machine-dependent
runs only on one type of computer
Often machine-independent
can run on many different
types of computers
Machine and assembly languages are low-level
Low-Level Languages
What is machine language?
p. 665 Fig. 13-2
Only language computer directly recognizes
Uses a series of binary digits (1s and 0s) with a combination of numbers and letters that represent binary digits
Low-Level Languages
What is assembly language?
p. 666 Fig. 13-3
Instructions made up of symbolic instruction codes, meaningful abbreviations and codes
Source program contains code to be converted to machine language
Procedural Languages
What is a procedural language?
p. 666
Most widely used are BASIC, COBOL, and C
Uses series of English-like words to write instructions
Often called third-generation language (3GL)
Programmer writes instructions that tell computer what to accomplish and how to do it
Procedural Languages
What is a compiler?
p. 667 Fig. 13-4
Program that converts entire source program into machine language before executing it
Procedural Languages
What is an interpreter?
p. 667 Fig. 13-5
Program that translates and executes one program code statement at
a time
Does not produce object program
Procedural Languages
What is COBOL?
p. 668 Fig. 13-6
Designed for business applications
English-like statements make code easy to read, write, and maintain
COmmon
Business-Oriented
Language
Procedural Languages
What is C?
p. 668 Fig. 13-7
Powerful language originally designed to write system software
Requires professional programming skills
Object-Oriented Programming Languages
What is an object-oriented programming (OOP) language?
p. 669
Used to implement
object-oriented design
Major benefit
is ability to reuse existing objects
Event-driven—checks for
and responds
to set of events
C++ and Java
are complete object-oriented languages
Object is
item that contains
data and procedures that act on data
Event is action to which program responds
Object-Oriented Programming Languages
What is Java?
p. 669 Fig. 13-8
Developed by Sun Microsystems
Similar to C++ but uses just-in-time (JIT) compiler to convert source code into machine code
Object-Oriented Programming Languages
What is C++?
p. 670 Fig. 13-9
Includes all elements of C, plus additional features
for working with object-oriented concepts
Used to develop
database and
Web applications
Object-Oriented Programming Languages
What is C#?
p. 670
Object-oriented programming language based on C++
Accepted as a standard for Web applications and XML-based Web services
Uses a JIT compiler
Resulting code is called Microsoft Intermediate Language (MSIL)
Object-Oriented Programming Languages
What is a visual programming language?
p. 670
Often used in RAD (rapid application development) environment
Sometimes called
fifth-generation language
Provides visual or graphical interface for creating source code
Object-Oriented Programming Languages
What is Visual Studio 2005?
p. 671 Fig. 13-10
.NET is set of technologies that allows program to run on Internet
Comprised of Visual Basic 2005, Visual C++ 2005, Visual C# 2005, and Visual J# 2005
Object-Oriented Programming Languages
What is Delphi?
p. 672 Fig. 13-11
Powerful visual programming tool
Ideal for large-scale enterprise and Web applications
Object-Oriented Programming Languages
What is PowerBuilder?
p. 673 Fig. 13-12
Another powerful visual programming tool
Best suited for Web-based and large-scale
object-oriented applications
Nonprocedural Languages
and Program Development Tools
What are nonprocedural languages and program development tools?
p. 670 and 674
Nonprocedural Language
The programmer writes English-like instructions or interacts with a visual environment to retrieve data from files or a database
Program Development Tools
User-friendly programs designed to assist both programmers and users in creating programs
Other Programming Languages
What is RPG (Report Program Generator)?
p. 674 Fig. 13-13
Nonprocedural language used for generating reports, performing computations, and updating files
Other Programming Languages
What is a fourth-generation language (4GL)?
p. 675 Fig. 13-14
Nonprocedural language that allows access to data in database
Popular 4GL is SQL, query language that allows users to manage data in relational DBMS
Other Programming Languages
What are other available programming languages?
p. 675
ALGOL
ADA
APL
FORTH
LISP
HYPERTALK
FORTRAN
LOGO
PASCAL
MODULA-2
PILOT
SMALLTALK
PROLOG
PL/I
Other Program Development Tools
What is an application generator?
p. 676 Fig. 13-16
Program that creates source code or machine code from specification
Consists of report writer, form, and menu generator
Form provides areas for entering data
Other Program Development Tools
What is Visual Basic for Applications (VBA)?
p. 676 - 677 Fig. 13-17
Macro programming language
Macro—series of statements used to automate tasks
Web Page Development
What is HTML (Hypertext Markup Language)?
p. 678 Fig. 13-18
Used to create Web pages
Web Page Development
How are special effects and interactive elements added to a Web page?
p. 679
Web Page Development
What is the common gateway interface (CGI)?
p.679 - 680 Fig. 13-19
Communications standard that defines how Web server communicates with outside sources
Step 3. When the user submits a request, it is sent to the CGI program. The CGI program contacts the database and requests information for the user. In this case, it looks for a movie titled The Wizard of Oz.
CGI script—program that manages sending and receiving across CGI
Web Page Development
What is a scripting language?
p. 681 Fig. 13-20
Typically easy to learn and use
JavaScript—adds dynamic content and interactive elements to Web page
VBScript (Visual Basic, Scripting Edition)—adds intelligence and interactivity to Web page
Perl (Practical Extraction and Report Language)—has powerful text processing capabilities
Web Page Development
What is dynamic HTML (DHTML)?
p. 682 Fig. 13-21
Allows developers to include more graphical interest and interactivity in Web page
Web Page Development
What are XHTML, XML, and WML?
p. 682 - 683
XHTML
(Extensible HTML)
enables Web sites to be displayed
more easily on microbrowsers
XML
(Extensible Markup Language)
allows developers to
create customized tags
WML
(Wireless Markup Language)
allows developers to design pages specifically for microbrowsers
Includes features of HTML and XML
Many PDAs and smart phones use WML as their markup language
Server sends entire record to client, enabling client to do much of processing without going back to server
Web Page Development
What is Web page authoring software?
p. 683
Creates sophisticated Web pages without using HTML
Generates HTML
Multimedia Program Development
What is multimedia authoring software?
p. 684 Fig. 13-22
Combines text, graphics, animation, audio, and video into interactive presentation
Used for computer-based training (CBT) and Web-based training (WBT)
Software includes Toolbook, Authorware, and Director MX
The Program Development Cycle
What is the program development cycle?
p. 685 Fig. 13-23
Steps programmers use to build computer programs
Programming team—Group of programmers working on program
Step 1 — Analyze Requirements
What is involved in analyzing the requirements?
p. 686 Fig. 13-24
Review requirements
Meet with systems analyst and users
Identify input, output, processing, and data components
IPO chart—Identifies program’s inputs, outputs, and processing steps
Step 2 — Design Solution
What is involved in designing the solution?
p. 687
Two
approaches
Devise solution algorithm, step-by-step procedure to solve problem
Step 2 — Design Solution
What is a hierarchy chart?
p. 687 Fig. 13-25
Shows program modules graphically
Also called structure chart
Step 2 — Design Solution
What is object-oriented (OO) design?
p. 688 Fig. 13-26
Programmer packages data and procedure into single unit, an object
Objects are grouped into classes
Class diagram represents hierarchical relationships of classes graphically
Step 2 — Design Solution
What is a sequence control structure?
p. 688 Fig. 13-27
Control structure that shows actions following each other in order
Control structure depicts logical order of program instructions
Step 2 — Design Solution
What is a selection control structure?
p. 689 Fig. 13-28
Tells program which action to take, based on a certain condition
Two types
Case control structure
If-then-else control structure—yields one of two possibilities: true or false
Step 2 — Design Solution
What is a case control structure?
p. 689 Fig. 13-29
Yields one of three or more possibilities
Step 2 — Design Solution
What is a repetition control structure?
p. 689 - 690 Figs. 13-30–13-31
Enables program to perform one or more actions repeatedly
Do-while control structure—repeats as long as condition is true
Do-until control structure—repeats until condition is true
Step 2 — Design Solution
What is a program flowchart?
p. 690 Fig. 13-32
Graphically shows logic
in solution algorithm
Step 2 — Design Solution
What is an example of a flowchart?
p. 690 - 691 Fig. 13-33
Step 2 — Design Solution
What is flowcharting software?
p. 690 - 691 Fig. 13-34
Used by programmers to develop flowcharts
Step 2 — Design Solution
What is pseudocode?
p. 690 Fig. 13-35
Uses condensed form
of English to convey program logic
Step 3 — Validate Design
What is involved in validating the design?
p. 693
Check program
design for accuracy
Logic error
design flaw
that causes
inaccurate results
Test data
sample data that
mimics real data that program will process
Programmer checks
logic for correctness
and attempts to uncover
logic errors
Desk check
programmers use test
data to step through logic
Inspection
systems analyst reviews deliverables during the system development cycle
Step 4 — Implement Design
What is implementation?
p. 693 - 695 Fig. 13-38
Writing the code that translates the design into a program
Syntax—rules that specify how to write instructions
Comments—program documentation
Extreme programming (XP)—coding and testing as soon as requirements are defined
Step 5 — Test Solution
What is involved in testing the solution?
p. 695 - 696
Ensure program runs correctly and is error free
Debugging—locating and correcting syntax and logic errors, or bugs
Test copy of program, called beta, sometimes used to find bugs
Step 6 — Document Solution
What is involved in documenting the solution?
p. 696
Programmer performs two activities
Reviews program code—removes dead code, program instructions that program never executes
Reviews
documentation
Summary of Programming Languages and Program Development
Various programming languages
used to write and develop
computer programs
The program development
cycle and the tools used to make
this process efficient
Web development and multimedia development tools
Chapter 13 Complete