Constants
Constants are named storage locations in memory, the value of which does not
change during program Execution. They remain the same throughout the program execution.
When the user wants to use a value that never changes, a constant can be declared
and created. The Const statement is used to create a constant. Constants can be
declared in local, form, module or global scope and can be public or private as
for variables. Constants can be declared as illustrated below.
Public Const gravityconstant As Single = 9.81
Predefined Visual Basic Constants
The predefined constants can be used anywhere in the code in place of the actual
numeric values. This makes the code easier to read and write.
For example consider a statement that will set the window state of a form to
be maximized.
Form1.Windowstate = 2
The same task can be performed using a Visual Basic constant
Form1.WindowState = vbMaximized
Data Type Conversion
Visual Basic functions either to convert a string into an integer or vice versa
and many more conversion functions. A complete listing of all the conversion functions
offered by Visual Basic is elucidated below.
Conversion To |
Function |
| Boolean |
Cbool |
| Byte |
Cbyte |
| Currency |
Ccur |
| Date |
Cdate |
| Decimals |
Cdec |
| Double |
CDbl |
| Integer |
Cint |
| Long |
CLng |
| Single |
CSng |
| String |
CStr |
| Variant |
Cvar |
| Error |
CVErr |
A conversion function should always be placed at the right hand side of the
calculation statement.
Visual Basic Built-in Functions
Many built-in functions are offered by Visual Basic fall under various categories.
These functions are procedures that return a value. The functions fall into the
following basic categories that will be discussed in the follwing sections at
length.
-
Date and Time Functions
-
Format Function
-
String Functions
