QBasic

1
QBasic

• Chapter 1 Introduction to Computer Systems
  QBasic

2
Introduction

• Importance of computers
• What is a computer?
• Computer Programs
• Programming Languages

3
What Computers Can Do

• Arithmetic Operations
• Comparison (logical) operations
• Storage retrieval operations
• Speed Accuracy

4
Components of a Computer System

• Hardware
• System Unit
• CPU control unit arithmetic logic unit
• Main Memory
• Peripheral Devices
• Input
• Output

5
Components of a Computer System

• Secondary Storage
• Floppy disk, hard drive, CD, DVD, Flash Drive
• Secondary Storage Devices
• Used to copy data to from secondary storage
• Storage space measured in Bytes
• Kilobyte, Megabyte, Gigabyte, Terabyte

6
Categories of Computer Systems

• Supercomputers
• Mainframes
• Minicomputers
• Microcomputers

7
Where Did All this Start?

• Operating System
• User Interface
• Command-Line Interface
• Graphical User Interface
• DOS Disk Operating System
• Command-line
• Used to run QBasic

8
QBasic

• Designed from the BASIC language
• Enhanced, menu-driven
• Online Help
• Structured language

9
Running QBasic

• Installed on your H drive
• Double click on QB.exe
• Use mouse and arrow keys to navigate
• Menu Bar
• File - Edit
• View - Search
• Run - Debug
• Options - Help

10
QBasic

• Title Bar
• Reference Bar
• Immediate Window

11
Menus

• File
• New
• Open
• Save
• Save As
• Print
• Exit

12
Menus

• View
• SUBs
• Split
• Output Screen
• Run
• Start
• Restart
• Continue

13
Entering Editing Programs

• Use CLS to clear screen at beginning
• Type commands one line at a time
• Hit Enter to go to next line
• Scroll up down as needed

14
Key Words in QBasic

• CLS
• INPUT
• PRINT
• Put text in double quotes
• Use semi-colon between quoted text variable
  names
• Use for text variables
• User, Instructor, Title

15
Being a Responsible Computer User

• Computer Ethics
• Hardware
• Backup data
• Store media properly
• Software
• Commercial Software
• Shareware
• Public-domain Software