1. Chapter 3 – Fundamental Statements
QBasic
Chapter 3 – Fundamental Statements

2. QBasic Statement Components
Keywords
Constants
Numeric constants
Real numbers – include decimal points
Integers – w/out decimal points
No commas, symbols (only – sign) or blank spaces
Exponential notation is used

3. QBasic Statement Components
Constants
Character string constants
Alphanumeric data
Only one set of double quotes
Length of a string – max 32,767 characters
Variables
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

4. QBasic Statement Components
Numeric Variables
Supplied by the programmer or
Calculated during program execution
Begins with a letter, followed by letters, digits, and periods
Cannot have blank spaces

5. QBasic Statement Components
String Variables
Stores character strings
Begins with a letter followed by letters or digits and always end with a $
Keywords
Cannot be used as variable names
READ, LIST, PRINT, LET and END

6. Simple QBasic Statements
CLS – Clear Screen
Documenting a Program
REM
Single quotation mark (‘)
Can be used anywhere in the program
REM **** This program was created by ***
‘ This program was created by

7. Simple QBasic Statements
Assigning Values to Variables
Assignment Statement
LET keyword is optional
LET Rate = .0825
LET Tuition = 50.00
Heading$ = “Inventory Report”
Classification = 4

8. Simple QBasic Statements
Arithmetic Operations
Composed of numeric constants, numeric variables, and arithmetic operators
+, -, /, *, ^
LET Tuition = Hours * 50
Order of Operations - PEMDAS

9. Simple QBasic Statements
Displaying Results
PRINT
PRINT Heading$, Tuition would result in:
Your tuition amount is
Displaying Literals
Group of characters containing just about anything
PRINT “JUNK $%^ 4567” would result in:
JUNK $%^ 4567

10. Simple QBasic Statements
END
Stops program execution
Immediate Window
Execute statements as soon as ENTER is pressed

11. Simple QBasic Statements
HELP
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