October 19, 2009

Constants, Data Type Conversion, Visual Basic Built-in Functions

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

Disclaimer:
The above article doesn't give you any guarantee and the sole purpose of this article is to share my learning in the way I understood. Any comments to refine this article are welcome with great pleasure. Please report any breaking link by commenting below.

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