QBasic

1
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 400.00
• 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