Discovering Computers 2008
Chapter 13
Programming
Languages and
Program Development
Applications vs. Program Languages
User Oriented
CPU Oriented
Program Language vs. Application
Procedural
Non-Procedural
Program Language vs. Application
You
Communicate
CPU
Application
Computer Programs and Programming Languages
What is a computer program?
 Series of instructions that tells CPU what to do
known as “perform tasks”
Created by a programmer using a programming
language
p. 664 Fig. 13-1
Next
Procedural Languages
What is debugging?
Process of locating
and correcting
syntax and logic
errors in program
Harvard University,
September 9, 1945
Why Program ??????
Communicate with programmer on the job
Customize software
Increase computer understanding
Increase software understanding
Promotion within the company
Challenging and Fun
Computer Programming Video
Computer Programs and Programming Languages
What are low-level languages and high-level languages?
High-level
language
Low-level
language
Machine and assembly languages
are low-level
Machine-dependent
runs only on one type of computer
p. 664
Next
Low-Level Languages
What is machine language?

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
A dump
p. 665 Fig. 13-2
Next
Low-Level Languages
What is assembly language?

Instructions made up of
symbolic instruction
codes, meaningful
abbreviations and codes

Source program contains
code to be converted to
machine language
p. 666 Fig. 13-3
Next
Computer Programs and Programming Languages
What are high-level languages?
High-level
language
Often machine-independent
can run on many different
types of computers and operating
systems
p. 665
Next
Procedural Languages
What is a procedural language?
Programmer writes
instructions that tell
computer what to accomplish
and how to do it
Uses series of English-like
words to write instructions
BASIC,
COBOL, and C
Next
Procedural Languages
What is COBOL?



p. 668
Designed for business applications
English-like statements make code easy to read, write,
and maintain
COmmon Business-Oriented Language
Procedural Languages
What is C?


Powerful language originally designed to write
operating system software
Requires professional programming skills
}
for(int b = 0; b < 1; b++)
{
outp(PortAddr, 50);
while((inp(PortAddr + 5) &
0x020) == 0);
}
for(int c = 0; c < 1; c++)
{
outp(PortAddr, 32);
while((inp(PortAddr + 5) & 0x020) == 0);
}
p. 668
Object-Oriented Programming Languages
What is an object-oriented programming (OOP) language?
Used to
implement
object-oriented
design
Object is
item that
contains
data and
procedures
that act on
data
p. 669
Major benefit
is ability to
reuse existing
objects
Event-driven—
checks for
and responds
to set of events
Java, C++, C#,
and Visual Basic
are complete
object-oriented
languages
Event is
action to
which
program
responds
Next
Object-Oriented Programming Languages
What is Java?

Developed by Sun
Microsystems

Similar to C++

Used to develop
Web applications
Click to view Web
Link, click Chapter 13, Click
Web Link from left
navigation, then click
Java below Chapter 13
p. 669 Fig. 13-8
Next
Object-Oriented Programming Languages
What is C++?


Includes all elements of C, plus additional features
for working with object-oriented concepts
Used to develop
database and
games because of its
speed; applications;
operating systems
Click to view Web
Link, click Chapter 13, Click
Web Link from left
navigation, then click
C++ below Chapter 13
p. 670 Fig. 13-9
Next
Object-Oriented Programming Languages
What is C#?

Object-oriented programming language based on C++

Accepted as a standard for Web applications and
XML-based Web services
Click to view Web
Link, click Chapter 13, Click
Web Link from left
navigation, then click
C# below Chapter 13
p. 670
Next
Other Programming Languages
and Development Tools
A 4GL (fourth-generation language) is a nonprocedural
language that enables users and programmers to
access data in a database
Structured
Query
Language
Portland.accdb
Other Programming Languages
and Development Tools
Classic programming languages include:
Ada
ALGOL
APL
BASIC
Forth
FORTRAN
HyperTalk
LISP
Logo
Modula-2
Pascal
PILOT
PL/1
Prolog
RPG
Smalltalk
Other Program Development Tools
What is a macro?


Series of statements that instructs an application how
to complete a task
Prevents creating the same task over and over again
How to create a simple macro in
Microsof Excel
p. 676 - 677 Fig. 13-17
Next
Web Page Development
What is HTML (Hypertext Markup Language)?

Used to create Web pages
Click to view Web
Link, click Chapter 13, Click
Web Link from left
navigation, then click
HTML below Chapter 13
p. 678 Fig. 13-18
Next
Web Page Development
What is the common gateway interface (CGI)?
 Communications standard
that defines how Web server
communicates with outside
sources

CGI script—program that
manages sending and receiving
across CGI
http://www.harrietcarter.com/
p.679 - 680 Fig. 13-19
Web Page Development
What is a scripting language?
 Typically easy to learn and use




JavaScript
Perl (Practical Extraction
and Report Language)
PHP (PHP: Hypertext
Preprocessor)
VBScript (Visual Basic,
Scripting Edition)
COD Script
p. 680 - 681 Fig. 13-20
Next
Web Page Development
What is Web page authoring software?


Creates sophisticated Web pages without using HTML
Generates HTML
Dreamweaver
p. 683
Expression
Web
Flash
Next
Web Page Development
Web 2.0 allows Web sites to provide a means for
users to:
Share personal
information
Allow users to
modify Web site
content
Have application
software built
into the site
Web Page Development
Most Web 2.0 sites use APIs Application Programming Interfaces
 An API enables programmers to interact with an
environment such as a Web site or operating system
Multimedia Program Development
What is multimedia authoring software?



Combines text,
graphics, animation,
audio, and video into
interactive presentation
Used for computerbased training (CBT)
and Web-based training
(WBT)
Software includes
Toolbook, Authorware,
and Director
Multimedia Presentation
p. 684 Fig. 13-22
The Program Development Cycle
What is the program development cycle?
 Steps programmers use to build computer programs

Programming
team—Group of
programmers
working on
program
p. 685 - 686 Fig. 13-23
Scientific Method?
Next
Structured Programming
Starting in the 1960s, a number of techniques evolved
to make program design more systematic and
programs themselves easier to read and maintain.
This type of design became known as
structured programming.
Avoid GOTO Statements
Step 1 — Analyze Requirements
What is involved in analyzing the requirements?
1. Review requirements
2. Meet with systems analyst and users
3. Identify input, output, processing, and data
components

p. 686 Fig. 13-24
IPO chart—
Identifies
program’s inputs,
outputs, and
processing steps
Next
Design Solution
The design of the program addresses all of the tasks the program must perform
and how to organize or sequence them when coding the program.
Design tools to plan the solution include:
Pseudocode
Flowcharts
Structure Charts
Step 2 — Design Solution
What is pseudocode?

Uses condensed form
of English to convey
program logic
p. 690 and 692 Fig. 13-35
Next
Design Solution - Pseudocode
Step 2 — Design Solution
What is a program flowchart?

Graphically shows logic
in solution algorithm
p. 690 Fig. 13-32
Next
Step 2 — Design Solution
What is flowcharting software?

Used by programmers to develop flowcharts
Click to view Web
Link, click Chapter 13, Click
Web Link from left
navigation, then click
Flowcharting Software
below Chapter 13
p. 690 - 691 Fig. 13-34
Next
Hierarchy Chart
Hierarchy charts depict the overall organization of a
program.
Program modules should be arranged hierarchically, in a
top-down design.
Step 2 — Design Solution
What is a hierarchy chart?


Shows program modules graphically
Also called structure chart
p. 687 Fig. 13-25
Next
Step 2 – Design Solution
What is structured design?
Technique that builds all
program logic from
combination of three basic
control structures
sequence
control
structure
selection
control
structure
repetition
control
structure
Step 2 — Design Solution
What is a sequence control structure?
 Control structure that shows actions following each
other in order

p. 688 Fig. 13-27
Control structure depicts
logical order of program
instructions
Next
Step 2 — Design Solution
What is a selection control structure?
 Tells program which
action to take, based
on a certain
condition
 Two types


p. 689 Fig. 13-28
Case control structure
If-then-else control
structure—yields one
of two possibilities:
true or false
Next
Step 2 — Design Solution
What is a repetition control structure?
 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 as
long as the condition is
false
p. 689 - 690 Figs. 13-30–13-31
Next
Step 3 — Validate Design
What is involved in validating the design?
Check program
design for accuracy
Desk check
programmers use test
data to step through logic
Test data
sample data that
mimics real data that
program will process
p. 693
Programmer checks
logic for correctness
and attempts to uncover
logic errors
Logic error
design flaw
that causes
inaccurate results
Inspection
systems analyst reviews
deliverables during the system
development cycle
Next
Step 4 — Implement Design
What is implementation?
 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
p. 693 - 694 Fig. 13-38
Next
Step 5 — Test Solution
Ensure program runs
correctly and is error free
Debugging is the process of
making sure a program is
free of errors, or “bugs”.
 Logic errors
 Syntax errors
Design
Code
Logic
Error
Debug
Document
Testing insures that the
programs work as planned.
 Alpha testing
 Beta testing
Syntax
Error
Step 6 — Document Solution
What is involved in documenting the solution?

Programmer performs two activities
Reviews program
code—removes dead
code, program
instructions that
program never executes
p. 696
Reviews
documentation
Next
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
Chapter 13 Complete
Web development and multimedia
development tools
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Discovering Computers 2008