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Using Variables, Constants, and Functions in Calculations. Chapter 2. Text Data Types. String stores up to 2 billion alphanumeric characters – letters, digits, and special characters. Byte stores 1 ASCII character.
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Using Variables, Constants, and Functions in Calculations Chapter 2
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.
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.
Default Values • Numeric – 0 • Boolean – False (-1) • Date – 12:00 AM January 1, 0001 • Object – null • String - null
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.
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.
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.
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
Using ComboBox values • Dim intTerm as Integer • intTerm = Val(cboTerm.Text)
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 Implicit (Predefined) Functions
InputBox Function Variable = InputBox(Prompt, [Title], [Default Response])
Arithmetic Operators • ^ Exponentiation • * Multiplication • / Division with floating point result • \ Division with an integer result • MOD – Result is the remainder of division • + Addition • - Subtraction
Format Function • Format (expression, “style”) • Style is either a: pre-defined format ie. currency or User defined format ie. $#,###.00