Dim Statement

Description

Declares variables and allocates storage space.

Syntax

Dim varname[([subscripts])][As type][,varname[([subscripts])][As type]] . . .

The Dim statement syntax has these parts:

Part	Description

varname	Name of the variable; follows standard variable naming conventions.
subscripts	Dimensions of an array variable; up to 60 multiple dimensions may be declared. The subscripts argument uses the following syntax:
	[lower To] upper [,[lower To] upper] . . .
type	Data type of the variable; may be Boolean, Integer, Long, Currency, Single, Double, Date, String (for variable-length strings), String * length (for fixed-length strings), Object, Variant, a user-defined type, or an object type. Use a separate As type clause for each variable you declare.

Remarks

Variables declared with Dim at the module level are available to all procedures within the module. At the procedure level, variables are available only within the procedure.

Use the Dim statement at module or procedure level to declare the data type or object type of a variable. For example, the following statement declares a variable as an Integer.

Dim NumberOfEmployees As Integer

If you do not specify a data type or object type, and there is no Deftype statement in the module, the variable is Variant by default.

When variables are initialized, a numeric variable is initialized to 0, a variable-length string is initialized to a zero-length string, and a fixed-length string is filled with zeros. Variant variables are initialized to Empty. Each element of a user-defined type variable is initialized as if it was a separate variable. A variable that refers to an object must be assigned an existing object using the Set statement before it can be used. Until it is assigned an object, the declared object variable has the special value Nothing, which indicates that it does not refer to any particular instance of an object.

You can also use the Dim statement with empty parentheses to declare dynamic arrays. After declaring a dynamic array, use the ReDim statement within a procedure to define the number of dimensions and elements in the array. If you try to redeclare a dimension for an array variable whose size was explicitly specified in a Private, Public or Dim statement, an error occurs.

Tip

When you use the Dim statement in a procedure, it is a generally accepted programming practice to put the Dim statement at the beginning of the procedure.

See Also

Array Function, Option Base Statement, Private Statement, Public Statement, ReDim Statement, Set Statement, Static Statement, Type Statement.

Example

This example shows various uses of the Dim statement to declare variables. The Dim statement is also used to declare arrays. The default lower bound for array subscripts is 0 and can be overridden at the module level using the Option Base statement.

' AnyValue and MyValue are declared as Variant by default with values
' set to Empty.
Dim AnyValue, MyValue

'  Explicitly declare a variable of type Integer.
Dim Number As Integer

' Multiple declarations on a single line. AnotherVar is of type Variant
' since its type is omitted.
Dim AnotherVar, Choice As Boolean, BirthDate As Date

' DayArray is an array of Variants with 51 elements indexed, 
' starting at 0 thru 50, assuming Option Base is set to 0 (default) for
' the current module.
Dim DayArray(50)

' Matrix is a two-dimensional array of integers.
Dim Matrix(3,4) As Integer
' MyMatrix is a three-dimensional array of doubles with explicit
' bounds.
Dim MyMatrix(1 To 5,  4 To 9,  3 To 5) As Double

' BirthDay is an array of dates with indexes from 1 to 10.
Dim BirthDay(1 To 10) As Date        

' MyArray is a dynamic array.
Dim MyArray()