Type Characters

Type Characters

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Visual Basic Programming Guide

Type Characters

In addition to specifying a data type in a declaration statement, you can force the data type of some programming elements with a type character. The type character must immediately follow the element, with no intervening characters of any kind.

The type character is not part of the name of the element. An element defined with a type character can be referenced without the type character.

Identifier Type Characters

Visual Basic supplies a set of identifier type characters, which you can use in a declaration to specify the data type of a variable or constant. The following table shows the available identifier type characters with examples of usage.

Identifier type character	Data type	Example
%	Integer	Dim L%
&	Long	Dim M&
@	Decimal	Const W@ = 37.5
!	Single	Dim Q!
#	Double	Dim X#
$	String	Dim V$ = "Secret"

No identifier type characters exist for the Boolean, Byte, Char, Date, Object, SByte, Short, UInteger, ULong, or UShort data types, or for any composite data types such as arrays or structures.

In some cases, you can append the $ character to a Visual Basic function, for example Left$ instead of Left, to obtain a returned value of type String.

In all cases, the identifier type character must immediately follow the identifier name.

Literal Type Characters

A literal is a textual representation of a particular value of a data type.

Default Literal Types

The form of a literal as it appears in your code ordinarily determines its data type. The following table shows these default types.

Textual form of literal	Default data type	Example
Numeric, no fractional part	Integer	2147483647
Numeric, no fractional part, too large for Integer	Long	2147483648
Numeric, fractional part	Double	1.2
Enclosed in double quotation marks	String	"A"
Enclosed within number signs	Date	#5/17/1993 9:32 AM#

Forced Literal Types

Visual Basic supplies a set of literal type characters, which you can use to force a literal to assume a data type other than the one its form indicates. You do this by appending the character to the end of the literal. The following table shows the available literal type characters with examples of usage.

Literal type character	Data type	Example
S	Short	I = 347S
I	Integer	J = 347I
L	Long	K = 347L
D	Decimal	X = 347D
F	Single	Y = 347F
R	Double	Z = 347R
US	UShort	L = 347US
UI	UInteger	M = 347UI
UL	ULong	N = 347UL
C	Char	Q = "."C

No literal type characters exist for the Boolean, Byte, Date, Object, SByte, or String data types, or for any composite data types such as arrays or structures.

Literals can also use the identifier type characters (%, &, @, !, #, $), as can variables, constants, and expressions. However, the literal type characters (S, I, L, D, F, R, C) can be used only with literals.

In all cases, the literal type character must immediately follow the literal value.

Hexadecimal and Octal Literals

The compiler normally construes an integer literal to be in the decimal (base 10) number system. You can force an integer literal to be hexadecimal (base 16) with the &H prefix, and you can force it to be octal (base 8) with the &O prefix. The digits that follow the prefix must be appropriate for the number system. The following table illustrates this.

Number base	Prefix	Valid digit values	Example
Hexadecimal (base 16)	&H	0-9 and A-F	&HFFFF
Octal (base 8)	&O	0-7	&O77

You can follow a prefixed literal with a literal type character. The following example shows this.

Dim counter As Short = &H8000S
Dim flags As UShort = &H8000US

In the previous example, counter has the decimal value of -32768, and flags has the decimal value of +32768.

Default Literal Types

Forced Literal Types

Tasks

Concepts

Reference

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