Learning Visual Basic .NET

Chapter 5. VB.NET Language Fundamentals

Chapter 2 demonstrates a very simple VB.NET program that prints the text string “Hello world!” to the console screen and provides a line-by-line analysis of that program. However, even that very simple program was complex enough that some of the details had to be skipped over. The current chapter begins an in-depth exploration of the syntax and structure of the VB.NET language.

Types

Every object you create or use in a VB.NET program must have a specific type (e.g., you must declare the object to be an integer or a string or a Dog or a Button). The type tells the compiler how big the object is and what it can do.

Types come in two flavors: those that are built into the language (intrinsic types) and types you create (classes, structs, and interfaces, discussed in Chapter 8, Chapter 12, and Chapter 13, respectively). VB.NET offers a number of intrinsic types, shown in Table 5-1.

Table 5-1. The intrinsic types

Type	Size (in bytes)	.NET type	Description
Boolean	1	Boolean	True or false.
Byte	1	Byte	Unsigned (values 0-255).
Char	2	Char	Unicode characters.
Date	8	DateTime	Midnight 1/1/0001 through 11:59:59 12/31/9999.
Decimal	12	Decimal	Fixed-precision numbers up to 28 digits and the position of the decimal point; typically used in financial calculations; requires the suffix “m” or “M.”
Double	8	Double	Double-precision floating-point numbers; holds the values from approximately +/-5.0 * 10-324 to approximately ...