1. Computer Science 1 Week 4

2. This Week ... QBasic Programming Computer Concepts Expressions
Software categories
Operating Systems
File Basics

4. Mathematical Equations and More
QBasic Expressions
Mathematical Equations and More

5. Functions of a Computer
Process Data
Store Data
Output Data

6. Expressions QBasic Expressions Operator Precedence
mathematical formulas
follows the format you know
Operator Precedence
order in which operators will be computed
practically all languages have precedence levels

7. QBasic vs. Other Languages
Not all programming languages have the same precedence levels
They are pretty consistent for basic algebra
So, make sure to consult the documentation

8. Numeric Operators in QBasic
Name ^
Exponent *
Multiplication /
Division +
Addition -
Subtraction & Unary Minus

9. Precedence Levels: Highest to Lowest
Operators
Precedence Name
(…)
Sub expression ^
Exponent -
Unary Minus
*, /
Multiplication & Division
+, -
Addition & Subtraction
Highest
Lowest

10. Calculate Results PRINT 11 * 2 + 8 * 4 - 7 PRINT 22 + 8 * 4 - 7

11. Calculate Results #2 PRINT 5 + 18 / 3 ^ 2 * 2 - 1

12. Calculate Results #3 PRINT 7 + 32 / 2 ^ 4 * (3 - 1)

13. Calculate Results With Variables
LET X = 10
LET Y = 2
PRINT X * 3 + -Y
PRINT X *
PRINT
PRINT

14. Example Program 1 DIM X, Y, Z LET X = 10 LET Y = 6
LET Z = X * 2 – 12 / Y
PRINT "The result:"; Z 20 2

15. Example Program 1 Output
The result: 18

16. Example Program 2 DIM X, Y, Z LET X = 2 LET Y = 5 LET Z = X*Y-(7–4)/3
PRINT "The result is"; Z

17. Example Program 2 Output
The result is 9

18. Example Program 3 DIM T1, T2, Ans LET T1 = 5 LET T2 = 4
LET Ans = T1*T2 + 5 – 6/3
PRINT "Answer:" ; Ans

19. Example Program 3 Output
Answer: 23

20. DIM Film AS String
DIM Tickets
DIM Cost
LET Film = "Revenge of the Nerds 4"
LET Tickets = 2
LET Cost = 9.50
PRINT Film
PRINT Tickets * Cost; " dollars"
LET is optional

21. Example Program 4 Output
Revenge of the Nerds 4
19 dollars

22. Expressions – Gumball Factory
QBasic Lab
Expressions – Gumball Factory

23. Lab: Gumball Factory Objectives Your Program use variables
use QBasic expressions
Your Program
helps a gumball factory compute the volume of a gumball

24. Gumball Math

25. Lab Requirements Remember: Turn the program & output in to:
you can help other students
however, you should figure this out on your own
Turn the program & output in to:
Lab 3 in SacCT

27. Software Basics
What is Software?

28. Software Major Categories
Application Software
works with the user to perform a task
example: Microsoft Word, Solitaire
System Software
runs programs & manages data
operating System – Windows, Mac-OS
Ready to spring to action

29. How Programs are Executed
Compiler
translates the program into the processor's instructions
Translated program is called object code
Interpreter
reads through the program
executes its own instructions on the processor 9

31. The Categories of Application Software29

32. Types of Software Document Production
Numerical Analysis – "Number Crunching"
Database
Reference & Educational
Entertainment
Emulators

33. Types of Software Internet security Simulators Business
Program Development
Music
Graphics
Video Editing

34. Document Production Software
Broad category that includes software used to create viewable documents
Examples:
word processing software
desktop publishing software
web authoring software 30

35. Numerical Analysis Software
designed to primarily perform "number crunching"
historically, this was a computer's original job
Examples:
spreadsheets
finance – tax preparation, money management
mathematical modeling 44

36. Numerical Analysis: Spreadsheets
grid-based model
examples: checkbooks, grades
To use spreadsheet software, you:
enter numbers
indicate how the computer should manipulate those numbers
Useful for quick numerical analysis

37. Database Software Database software Examples:
designed to organize information
used extensively in all businesses, institutions, etc....
Examples:
Microsoft Access
My SQL
Oracle

38. Educational Software Educational software Examples:
helps users learn and practice new skills
can include quizzes, activities, etc...
Examples:
software to learn reading
spoken language software
test preparation – SAT, GMAT, LSAT

39. Reference Software Reference software Examples: provides information
helps find and organize data
Examples:
encyclopedias
dictionaries
medical software

40. Entertainment Software
any software that is designed to be fun! ...woo hoo!
very broad category
Some statistics:
U.S. computer and video game software sales generated $10.5 billion in 2009
67% of American households play computer or video games
In 2010, 26% of Americans over the age of 50 play video games
about 40% are women 59

41. Entertainment Software: Games
Role-playing
Action
Adventure
Simulation
Sports
Puzzle
Strategy

42. World of Warcraft 12 million subscribers world wide
Machines running the game
5000 people maintain the game (September 2009)
World of Warcraft

43. Emulation Software Emulation software Examples:
software creates a computer inside a computer
emulated computer functions exactly like the original
excellent for running software when no hardware exists
Examples:
Vice – Commodore 64
Stella – Atari 2600

44. Stella
Atari 2600 Emulator

45. Simulation Software Simulation Software
recreates a real-world device in the computer
attempts to act exactly like the original
Requires great detail for accuracy
Examples:
Microsoft Flight Simulator
chemistry software

46. Microsoft Flight Simulator X

47. Program Development Software
provides tools used to write software
normally includes a compiler or interpreter
Examples:
Microsoft Visual Studio
BlueJ - Java
QBasic Lite – yippie! 7

48. Business Software Vertical market software Horizontal market software
software that works for a specific type of business
examples: glass mixing software, banking, …
Horizontal market software
software that any business can use
examples: accounting, project management

49. Business Software Groupware
software that helps different companies work together
also called collaborative software
example: Lotus Notes

50. Graphics Software Graphics software Examples:
lets you edit pictures, drawings, photos, etc...
used to enhance applications, websites, documents ....
Examples:
drawing software
photo editing software
CAD software (computer-aided design)

51. Inkscape

52. Music Software Audio editing software Examples:
create and edit digital audio and music
help write music sheets
Examples:
ear training software
audio encoding software
sheet music developers 53

53. Video Software Video Software Examples: designed to play video files
every computer has these
Examples:
Windows Media Player
Real Player
QuickTime 55

54. Video Software Video Editing Software Examples:
helps transfer video footage
allows video segments to be assembled and edited
adds special visual effects and sound tracks
Examples:
Adobe Premier
Microsoft Movie Maker
DVD authoring software - create interactive menus 55

56. Software Licenses
What Are Your Rights?

57. Software Licenses
A software license is a legal contract that defines the ways in which you may use a computer program
A shrink-wrap license goes into effect as soon as you open the packaging 71

58. Different Types of Software Licenses
Proprietary software
Shareware
Freeware
Open source software
Public domain software 73

59. Proprietary License Proprietary license Variants exist for:
license used by commercial software
allows you to use software you purchased
this is the most common license used
Variants exist for:
single users
multiple users

60. Shareware License Shareware license Typical attributes of shareware
allows you to test a program for free
expected purchase a copy if you want to use it
Typical attributes of shareware
many shareware applications will "expire"
the program may be limited in some way
produced documents may be "marked"

61. Freeware License Freeware license Sometimes there are a few rules:
means the software offered without any charge
there may be an advanced commercial version
Sometimes there are a few rules:
you cannot sell the software to others
you cannot sue the creator of the software

62. Open Source License Open source license Why open the source?
the source code can be downloaded
usually used by programmers
Why open the source?
multiple programmers can work on it
helps find bugs

63. Public Domain License Public domain license Examples
software is not owned by any company or person
legally classified as "not copy written"
also applies to really, really old software
Examples
computer science algorithms
old, old software

65. The Main System Software
Operating Systems
The Main System Software

66. What an Operating System Does
Master controller for all of the activities that take place within a computer
Basic Duties:
memory management
track resources
communicate with devices
interact with application software
interact with the user 14

67. Memory Management Prevent memory leaks Otherwise …
data from one program will overwrite another program or its data
data can also be misplaced
Otherwise …
data can get corrupted
programs can “crash”
General Protection Fault 16

68. Tracking Resources Remembers the names and locations of all your files
Keeps track of empty spaces where new files can be stored
Acts as a filing clerk 17

69. Communicate with Devices
Helps applications work better
they do not need to know the details of a device
e.g. the brand of printer
Scheduling
control input and output – order and access
some peripherals can only be used by one program at a time – e.g. printers 18

70. Drivers Communicate with Devices
small programs used to communicate with devices
usually provided by the manufacturer
Why do we need them?
devices might be implemented differently
the OS cannot know every device beforehand
Operating System  Driver  Device

71. Interact with Applications
Necessary for multi-tasking systems
Application Program Interface
application can tell the OS to perform a task
makes applications faster and smaller
the OS can send messages to the application
Application  OS  Driver  Device

72. Interact With The User The User Interface Classifications
combination of hardware and software
helps users and computers communicate
called the shell of the operating system
Classifications
Graphical User Interface - GUI
Command-line User Interface 19

73. Microsoft Windows Created by Microsoft
Major operating system on Intel-PCs
Where used:
designed for general computer users
designed for desktop / laptop PCs

74. Microsoft Windows Major versions: Windows 3.1 – 1991 Windows 95 – 1995
Windows XP – 2001
Windows Vista – 2007
Windows 7 – 2010

75. Windows XP

76. Windows 7
Beta Build 7000

77. Windows 1

78. Linux UNIX was developed in 1969 Linux was developed in 1991
originated AT&T’s Bell Labs
used extensively on mainframes
Linux was developed in 1991
port to modern computers
modern computers are more powerful than 1969 mainframes
General Public License (GPL) 25

79. Linux Multiple versions by multiple companies Where used: Red Hat
Ubuntu
etc....
Where used:
popular as an alternative to Windows
mostly used for small servers & CSc workstations

80. Red Hat Linux

81. Ubuntu Linux

82. Apple Mac-OS
Created by the Apple Corporation for the Macintosh Computer
Major Versions:
System 1 – 1984
System 6 – 1988
System 7 – 1991
Mac-OS X – 2001

83. 24

84. Handheld Operating Systems
Palm OS
came out with the Palm Pilot
runs on a numerous PDAs
Windows CE
CE = Compact Edition
simplified version of Windows

85. Android
Android:
is a mobile operating system initially developed by Android Inc. Android was bought by Google in 2005.
Android is based upon a modified version of the Linux kernel
Android Market: on-line software store that has 200,000 apps
2.5 billion total downloads.

86. iOS (Apple’s iPhone OS)
iOS (known as iPhone OS prior to June 2010) is Apple's mobile operating system. Originally developed for the iPhone, it has since been extended to support other Apple devices such as the iPod touch, iPad and Apple TV.
As of January 14, 2011, Apple's App Store contains more than 300,000 iOS applications.
Downloaded more than 10 billion times.
In the last quarter of 2010, it had a 16% share of the smartphone operating system market in terms of units sold, third behind Google's Android and Symbian (Nokia).

88. File Basics
Understanding Files

89. Logical Storage Metaphor
how files are stored is alien to humans
we need to visualize how data is stored
this "humanizes" the computer
Desktop metaphor
the most common metaphor
data is stored in files
folders store files and other folders

90. Other Common Metaphors
Tree metaphor
data is stored in leaves
leaves are stored on branches
Metaphor can be anything
... that allows "stuff" to be put in other "stuff"
other metaphors can exist

91. Microsoft BOB
Room Metaphor

92. Microsoft BOB
Room Metaphor

93. File Management Utilities
Part of the Operating System
"Explorer" in Windows
"Finder" in Mac-OS
Helps you
locate files
discover file properties
move, copy, rename, delete

94. Data Files Contain words, numbers & pictures Examples:
can be viewed, edited, printed, etc...
created with application software
Examples:
Microsoft Word document
Music file – e.g. MP3

95. Executable Files Contains instructions
these instructions run on the processor
are basically 1's and 0's
These are the application and system software files

96. Scripting Files Data files that are executed Examples:
do not run directly on a processor
requires an application to interpret them
Examples:
JavaScript
QBasic data files

97. Active vs. Passive Files
Active files
are active – they do something
instructions stored in a file
Includes scripting files
Passive Files
they do not instruct the computer
they just contain data

99. File Names
What's in a label?

100. File Names File-naming Convention
rules that determine if a filename is valid
some symbols are not allowed
each operating system has one
Every file has a name, and might also have a file extension

101. File Extensions File extension describes the file's type
essentially, what the file is used for
different file types can have different structures
Software often has a native file format
QBasic Lite uses qb files
Microsoft Word uses doc files

102. Special Symbols in Windows
The period denotes the file extension
Files can have multiple periods
but only the last one denotes the extension
It’s still a good idea not to use periods

103. Example File Name
Assignment 1.doc
File name
Period
Extension

104. Some Common Extensions
Description
.exe
Executable – a Program
.doc
Microsoft Word Document
.mp3
Audio File
.txt
Text File
.qb
QBasic Lite File

105. Drives Windows uses a letter to represent secondary storage
A is used for a floppy disk drive
C is used for the hard drive
D through Z are used for additional storage
CD and DVD drive letters vary

106. Moving-Head Disk (hard drive)

107. Folders Files are organized using folders
can contain files
or other folders
Root directory is the "main" folder
the term "directory" is an older term
"folder" metaphor came from the GUI

108. Special Symbols in Windows
The colon is used to denote a drive
Examples
C :
D :

109. Special Windows Symbols in Windows
The backslash is used to separate folder names
The Internet uses the forward slash "/"

110. C:\My Documents\CSUS\Paper.doc
File Specification
Drive Letter
File Name
C:\My Documents\CSUS\Paper.doc
describes the contents
Separated by a dot
Readme.txt, Newsletter.doc
Related to
Related to the file format, the arrangement of data in a file, and the coding scheme used to represent the data
Most software programs have a native file format that is used to store files
They display any files that have the filename extension for its native file format
Extension
Folders

112. Finding Files on Your Computer
File Patterns
Finding Files on Your Computer

113. Pattern Symbols The asterisk is a wildcard character
represents zero-or-more characters
essentially matches anything
The question mark is the placeholder
represents a single character

114. Wildcard Example
*.*
lab 4.qb
report.doc
qbasic.exe
index.htm

115. Wildcard Example 2 *.doc Assignment 1.doc Recipe.doc
Tappa Kegga Bru.doc
CSc 1.doc

116. Wildcard Example 3
CSc?.*
CSc1.doc
CSc6.htm
CSc5.qb
CScA.txt

117. Wildcard Example 4 *.htm* index.htm contact.html syllabus.htm
The L was found

118. Pattern in Action
*.qb