Writing Word Macros, Second Edition

Variables and Data Types

A variable can be thought of as a memory location that can hold values of a specific type. The value in a variable may change during the life of the program—hence the name “variable.”

In VBA, each variable has a specific data type, which indicates which type of data it may hold. For instance, a variable that holds text strings has the data type String and is called a string variable. A variable that holds integers (whole numbers) has the data type Integer and is called an integer variable. For reference, Table 5-1 shows the complete set of VBA data types, along with the amount of memory that they consume and their range of values. (I will discuss a few of the more commonly used data types in a moment.)

Table 5-1. VBA Data Types

Type	Size in Memory	Range of Values
Byte	1 byte	0 to 255
Boolean	2 bytes	True or False
Integer	2 bytes	–32,768 to 32,767
Long (long integer)	4 bytes	–2,147,483,648 to 2,147,483,647
Single (single-precision real)	4 bytes	Approximately –3.4E38 to 3.4E38
Double (double-precision real)	8 bytes	Approximately –1.8E308 to 4.9E324
Currency (scaled integer)	8 bytes	Approximately –922,337,203,685,477.5808 to 922,337,203,685,477.5807
Date	8 bytes	1/1/100 to 12/31/9999
Object	4 bytes	Any Object reference
String	Variable length: 10 bytes + string length; fixed length: string length	Variable length: <= about 2 billion (65,400 for Win 3.1); fixed length: up to 65,400
Variant	16 bytes for numbers 22 bytes + string ...