Visual

MANUAL TITLE
COURSE GUIDE – PROGRAMMING WITH DOCUMENT NO. : CAG 06H
SARADHA VISUAL BASIC REV. NO.: R0 DATE: 23/07/2020
GANGADHARAN
COPY :
COLLEGE DOCUMENT TITLE
PAGE 18 OF 70
UNIT II
BASIC PROGRAMMING CONCEPTS
Edition : 1




VB.Net Data Types
Data types is used for declaring variables or functions of different types. The type of a variable
determines how much space it occupies in storage and how the bit pattern stored is interpreted. VB.Net
provides a wide range of data types. The following table shows all the data types available:


Data Type Storage Allocation Value Range

Boolean Depends on implementing platform True or False

Byte 1 byte 0 through 255 (unsigned)

Char 2 bytes 0 through 65535 (unsigned)

Date 8 bytes 0:00:00 (midnight) on January 1, 0001
through 11:59:59 PM on December 31, 9999

Decimal 16 bytes 0 through +/-
79,228,162,514,264,337,593,543,950,335 (+/-
7.9...E+28) with no decimal point; 0 through
+/-7.9228162514264337593543950335 with
28 places to the right of the decimal

Double 8 bytes -1.79769313486231570E+308 through -
4.94065645841246544E-324, for negative
values
4.94065645841246544E-324 through
1.79769313486231570E+308, for positive
values

Integer 4 bytes -2,147,483,648 through 2,147,483,647
(signed)

Long 8 bytes -9,223,372,036,854,775,808 through
9,223,372,036,854,775,807(signed)

Object 4 bytes on 32-bit platform Any type can be stored in a variable of type
8 bytes on 64-bit platform Object
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PREPARED/REVISED BY : F. Jeno Sandana Brina Rouvier REVIEWED & APPROVED BY : D. Saraswathi
DESIGNATION : Asst. Prof. – B.C.A DESIGNATION : Asst. Prof. – M.Sc(CS)
DATE : 21/07/2020 DATE : 23/07/2020

, MANUAL TITLE
COURSE GUIDE – PROGRAMMING WITH DOCUMENT NO. : CAG 06H
SARADHA VISUAL BASIC REV. NO.: R0 DATE: 23/07/2020
GANGADHARAN
COPY :
COLLEGE DOCUMENT TITLE
PAGE 19 OF 70
UNIT II
BASIC PROGRAMMING CONCEPTS
Edition : 1




SByte 1 byte -128 through 127 (signed)

Short 2 bytes -32,768 through 32,767 (signed)

Single 4 bytes -3.4028235E+38 through -1.401298E-45 for
negative values;
1.401298E-45 through 3.4028235E+38 for
positive values

String Depends on implementing platform 0 to approximately 2 billion Unicode
characters

UInteger 4 bytes 0 through 4,294,967,295 (unsigned)

ULong 8 bytes 0 through 18,446,744,073,709,551,615
(unsigned)

User-Defined Depends on implementing platform Each member of the structure has a range
determined by its data type and independent
of the ranges of the other members

UShort 2 bytes 0 through 65,535 (unsigned)


Ex: Dim b As Byte
Dim n As Integer
b=1
n = 1234567

Boxing and Unboxing

 With Boxing and unboxing one can link between value-types and reference-types by allowing
any value of a value-type to be converted to and from type object.
 Converting a value type to reference type is called Boxing and vice-versa is Unboxing.

DimI AsInteger= 1
DimobjAsObject= I ' boxing
Dimj AsInteger=CInt(obj) ' unboxing
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The VB.Net Keyword



PREPARED/REVISED BY : F. Jeno Sandana Brina Rouvier REVIEWED & APPROVED BY : D. Saraswathi
DESIGNATION : Asst. Prof. – B.C.A DESIGNATION : Asst. Prof. – M.Sc(CS)
DATE : 21/07/2020 DATE : 23/07/2020

, MANUAL TITLE
COURSE GUIDE – PROGRAMMING WITH DOCUMENT NO. : CAG 06H
SARADHA VISUAL BASIC REV. NO.: R0 DATE: 23/07/2020
GANGADHARAN
COPY :
COLLEGE DOCUMENT TITLE
PAGE 20 OF 70
UNIT II
BASIC PROGRAMMING CONCEPTS
Edition : 1




Keywords are reserved words with special meaning in a programming language, they cannot be used as
tokens for such purposes as naming variables and subroutines. Visual Basic is built using keywords.
VB.NET keywords are shown in the Table. You can use them to build your programs.
AddHandler AddressOf Alias And AndAlso As Boolean
ByRef Byte ByVal Call Case Catch CBool
CByte CChar CDate CDec CDbl Char CInt

Variables in VB.NET
A variable is a name given to reserve a memory place that our programs can manipulate. Each variable
in VB.Net has a specific type, which determines the size and layout of the variable's memory; the
range of values that can be stored within that memory; and the set of operations that can be applied to
the variable.

Variable Declaration in VB.Net
The Dim statement is used for variable declaration and storage allocation for one or more variables.

Syntax : Dim var-name as data type
Ex: Dim pi as double
Pi = 3.14
Variable identifiers may be suffixed with type characters that serve to indicate the variable's type.
For example, declares a variable of type Integer: Dim x%

Ex:
Public Class Form1
Dim a, b, c As Integer

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load

End Sub

Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Handles Button1.Click
a = Val(TextBox1.Text)
b = Val(TextBox2.Text)
c = Val(TextBox1.Text) + Val(TextBox2.Text)
End Sub

Private Sub TextBox3_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Handles TextBox3.Click
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TextBox3.Text = Val(TextBox1.Text) + Val(TextBox2.Text)
End Sub




PREPARED/REVISED BY : F. Jeno Sandana Brina Rouvier REVIEWED & APPROVED BY : D. Saraswathi
DESIGNATION : Asst. Prof. – B.C.A DESIGNATION : Asst. Prof. – M.Sc(CS)
DATE : 21/07/2020 DATE : 23/07/2020