Using Variables, Constants, and Functions in Calculations

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Using Variables, Constants, and Functions in
Calculations

• Chapter 2

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Text Data Types

• String stores up to 2 billion alphanumeric
  characters letters, digits, and special
  characters.
• Byte stores 1 ASCII character.
• Char stores 1 unicode character includes 65,000
  characters consisting of many languages.

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Visual Basic .NET Data Types
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Visual Basic .NET Data Types
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Visual Basic .NET Data Types
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Visual Basic .NET Data Types
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Declaring Variables

• You must declare or create a variable before you
  can use it.
• Accessibility VariableName As Type Initial
  Value
• Accessibility defines what procedures have access
  to the value stored in the variable.
• Dim or Private
• Initial Value is optional.

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Default Values

• Numeric 0
• Boolean False (-1)
• Date 1200 AM January 1, 0001
• Object null
• String - null

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Variable Declaration

• Explicit means you must use the Dim statement
  before you can use the variable.
• Implicit means you can use the variable without a
  Dim statement. It will default to the Object data
  type.
• You must use Option Explicit Off statement for
  implicit declaration.
• Explicit variable declaration is one method of
  minimizing errors in your application.

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Local Variable

• Accessibility specifies which program statements
  will have access to the value stored in the
  variable.
• Accessibility is also called variable scope.
• A variable is a local variable and has procedure
  scope if it is declared within a procedure.
• The Dim statement declares a local variable.

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Module Level Variable

• A module (or form) level variable is accessible
  to any procedure within a form.
• A variable is a module level variable and has
  module scope if it is declared in the Form
  Declarations section.
• The Private statement declares a module level
  variable.

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Declaring Constants

• Local Constant defined in procedure
• Const conName As datatype expression
• Module (form) level constant defined in General
  Declarations section
• Private Const conName As datatype expression

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Using ComboBox values

• Dim intTerm as Integer
• intTerm Val(cboTerm.Text)

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Implicit (Predefined) Functions

• A function is a procedure that returns a value.
• Arguments are values supplied to the function.
• Functions are used to simplify calculations.
• Variable Val(argument)

• Val
• Format
• InputBox
• MsgBox
• IPmt
• Pmt
• Ppmt

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InputBox Function

• Variable InputBox(Prompt, Title, Default
  Response)

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Arithmetic Operators

• Exponentiation
• Multiplication
• / Division with floating point result
• \ Division with an integer result
• MOD Result is the remainder of division
• Addition
• - Subtraction

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Format Function

• Format (expression, style)
• Style is either a
• pre-defined format ie. currency
• or
• User defined format ie. ,.00

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Pre-defined Formats
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Pre-defined Formats
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User-defined Format Characters