QBasic
Chapter 3 –
Fundamental
Statements
QBasic Statement Components
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Keywords
Constants
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Numeric constants
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Real numbers – include decimal points
Integers – w/out decimal points
No commas, symbols (only – sign) or blank spaces
Exponential notation is used
QBasic Statement Components
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Constants
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Character string constants
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Alphanumeric data
Only one set of double quotes
Length of a string – max 32,767 characters
Variables
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Can only store one value at a time
Referred to by addresses
Variables are named
Only first 40 characters are recognized in QBasic
QBasic does not differentiate between upper & lowercase
Use descriptive variable names
QBasic Statement Components
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Numeric Variables
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Supplied by the programmer or
Calculated during program execution
Begins with a letter, followed by letters, digits, and
periods
Cannot have blank spaces
QBasic Statement Components
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String Variables
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Stores character strings
Begins with a letter followed by letters or digits
and always end with a $
Keywords
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Cannot be used as variable names
READ, LIST, PRINT, LET and END
Simple QBasic Statements
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CLS – Clear Screen
Documenting a Program
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REM
Single quotation mark (‘)
Can be used anywhere in the program
REM **** This program was created by ***
‘ This program was created by
Simple QBasic Statements
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Assigning Values to Variables
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Assignment Statement
LET keyword is optional
LET Rate = .0825
LET Tuition = 50.00
Heading$ = “Inventory Report”
Classification = 4
Simple QBasic Statements
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Arithmetic Operations
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Composed of numeric constants, numeric
variables, and arithmetic operators
+, -, /, *, ^
LET Tuition = Hours * 50
Order of Operations - PEMDAS
Simple QBasic Statements
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Displaying Results
PRINT
PRINT Heading$, Tuition
Your tuition amount is 400.00
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would result in:
Displaying Literals
Group of characters containing just about
anything
PRINT “JUNK $%^ 4567”
would result in:
JUNK $%^ 4567
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Simple QBasic Statements
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END
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Stops program execution
Immediate Window
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Execute statements as soon as ENTER is
pressed
Simple QBasic Statements
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HELP
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F1 key or HELP menu
Highlight menu option & then press F1 or right
mouse button
Press ESC to close HELP screen
Alt-H for list of HELP topics
Smart Editor