ASP.NET With Visual Basic: Operators and Operands

	Operators and Operands

Fundamental Visual Basic Operators

Introduction

An operation is an action performed on one or more values either to modify the value held by one or both of the variables, or to produce a new value by combining existing values. Therefore, an operation is performed using at least one symbol and at least one value. The symbol used in an operation is called an operator. A value involved in an operation is called an operand.

A unary operator is an operator that performs its operation on only one operand. An operator is referred to as binary if it operates on two operands.

The Line Continuation Operator: _

If you plan to write a long piece of code, to make it easier to read, you may need to divide it in various lines. You can do it as you would in any text editor. Here is an example:

<%
Dim Message

Message =
          "Welcome to our website."
%>

You can use the line continuation operator represented by a white space followed by an underscore and an empty space. Here is an example:

<%
    Dim Message

    Message = _
            "Welcome to our website."
%>

The Colon Operator :

To make various statements easier to read, you usually write each on its own line. The Visual Basic language allows you to write as many statements as possible on the same line. To do this, the statements must be separated by colons. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Kolo Bank - Customer Record</title>

</head>
<body>

<h2>Kolo Bank - Customer Record</h2>

<%

Dim CustomerName
Dim AccountNumber

CustomerName = "James Reinder" : AccountNumber = "928-3947-025"

Response.Write("Customer: ") : Response.Write(CustomerName) : Response.Write(" - ") : Response.Write(AccountNumber)
%>

</body>
</html>

This would produce:

Incrementing a Variable

String Concatenation: &

The & operator is used to add two strings or expressions. This is considered as concatenating them. The formula to follow is:

value1 & value2

To display a concatenated expression, use the assignment operator on the field. To assign a concatenated expression to a variable, use the assignment operator the same way:

<%
    Dim FirstName
    Dim LastName 
    Dim FullName 
    
    FirstName = "Francis "
    LastName = "Pottelson"
    FullName = FirstName & LastName
%>

To concatenate more than two expressions, you can use as many & operators between any two strings or expressions as necessary. After concatenating the expressions or values, you can assign the result to another variable or expression using the assignment operator.

Carriage Return-Line Feed

If you are displaying a string but judge it too long, you can segment it in appropriate sections as you see fit. To do this, use vbCrLf.

Using a Tab

To get the effect of pressing the Tab key on the computer keyboard, you can use the vbTab operator of the Visual Basic language.

The Addition Operation

Introduction

The positive operator is used as a unary operator to indicate that a number is positive. The addition operation, represented by the + symbol, is used to add numeric values.

Incrementing a Variable

To increment a value, add 1 to it. After adding 1, the value or the variable is (permanently) modified and the variable would hold the new value. This is illustrated in the following example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Incrementing a Variable</title>

</head>
<body>

<h2>Incrementing a Variable</h2>

<%
Dim Value = 12

Response.Write("Techniques of incrementing a value")
Response.Write("<br>Value = ")
Response.Write(Value)

Value = Value + 1

Response.Write("<br>Value = ")
Response.Write(Value)
%>

</body>
</html>

This would produce:

Incrementing a Variable

Compound Addition

As you may be aware aready, you can add a constant value to a variable. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Compound Addition</title>

</head>
<body>

<h2>Compound Addition</h2>

<%
Dim Value = 12.75
Dim NewValue As Double

Response.Write("Techniques of incrementing and decrementing a value")
Response.Write("<br>Value = ")
Response.Write(value)

NewValue = Value + 2.42

Response.Write("<br>Value = ")
Response.Write(NewValue)
%>

</body>
</html>

This would produce:

Compound Addition

To add a value to a variable and change the value that the variable is holding, you can combine the assignment "=" and the addition "+"ť operators to produce a new operator as +=. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Compound Addition</title>

</head>
<body>

<h2>Compound Addition</h2>

<%
Dim Value = 12.75
Dim NewValue As Double

Response.Write("Techniques of incrementing and decrementing a value")
Response.Write("<br>Value = ")
Response.Write(Value)

Value += 2.42

Response.Write("<br>Value = ")
Response.Write(Value)
%>

</body>
</html>

This code would produce the same result as above.

The Subtraction Operations

Introduction

The negative operator must be used to indicate that a number is negative. Examples are -12, -4.48, or -32706. The subtraction operation is used to take out or subtract a value from another value.

Decrementing a Variable

Decrementing a variable consists of subtracting 1 from it. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Decrementing a Variable</title>

</head>
<body>

<h2>Decrementing a Variable</h2>

<%
Dim Value = 12

Response.Write("Techniques of decrementing a value")
Response.Write("<br>Value = ")
Response.Write(Value)

Value = Value - 1

Response.Write("<br>Value = ")
Response.Write(Value)
%>

</body>
</html>

This would produce:

Decrementing a Variable

Compound Subtraction

To decrement a value from a variable, use the -= operator. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Exercises</title>

</head>
<body>

<h2>Exercises</h2>

<%
Dim Value = 12.75

Response.Write("Techniques of incrementing and decrementing a value")
Response.Write("<br>Value = ")
Response.Write(Value)

Value -= 2.42
		
Response.Write("<br>Value = ")
Response.Write(Value)
%>

</body>
</html>

This would produce:

Compound Subtraction

The Multiplication Operations

Introduction

The multiplication allows adding one value to itself a certain number of times, set by a second value. Like the addition, the multiplication is associative: a * b * c = c * b * a.

Exponentiation ^

Exponentiation is the ability to raise a number to the power of another number. This operation is performed using the ^ operator (Shift + 6). It uses the following formula:

y^x

In Microsoft Visual Basic, this formula is written as:

y^x

and means the same thing. Either or both y and x can be values, variables, or expressions, but they must carry valid values that can be evaluated.

Compound Multiplication

As seen with the addition, you can multiply a constant value by a variable. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Exercises</title>

</head>
<body>

<h2>Exercises</h2>

<%
Dim Value = 12.75

Response.Write("Value = ")
Response.Write(Value)

Value = Value * 2.42

Response.Write("<br>Value = ")
Response.Write(Value)
%>

</body>
</html>

This would produce:

Compound Multiplication

To make this operation easy, the C# language supports the compound multiplication assignment operator represented as *=. To use it, apply the *= operator to the variable and assign the desired value. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Exercises</title>

</head>
<body>

<h2>Exercises</h2>

<%
Dim Value = 12.75

Response.Write("Value = ")
Response.Write(Value)

Value *= 2.42

Response.Write("<br>Value = ")
Response.Write(Value)
%>

</body>
</html>

The Division Operation

Introduction

The division operation consists of cutting a number in pieces or fractions. When performing the division, be aware of its many rules. Never divide by zero (0). Make sure that you know the relationship(s) between the numbers involved in the operation.

Integer Division \

The Visual Basic language supports two types of divisions. If you want the result of the operation to be a natural number, called an integer, use the backlash operator "\" as the divisor. The formula to follow is:

Value1 \ Value2

This operation can be performed on two types of valid numbers, with or without decimal parts. After the operation, the result would be a natural number. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Exercises</title>

</head>
<body>

<h2>Exercises</h2>

<%
Dim Numerator = 12.75, Denominator = 3.59
Dim Division = Numerator \ Denominator

Response.Write(CStr(Numerator) & " \ " & CStr(Denominator) & " = " & CStr(Division))
%>

</body>
</html>

This would produce:

Integer Division

Decimal Division /

The second type of division results in a decimal number. It is performed with the forward slash "/". Its formula is:

Value1 / Value2

After the operation is performed, the result is a decimal number. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Exercises</title>

</head>
<body>

<h2>Exercises</h2>

<%
Dim Numerator = 12.75, Denominator = 3.59
Dim Division = Numerator / Denominator

Response.Write(CStr(Numerator) & " / " & CStr(Denominator) & " = " & CStr(Division))
%>

</body>
</html>

This would produce:

Decimal Division

Compound Division

As you can add, subtract, or multiply a value to a variable and assign the result to the variable itself, you can also divide a variable by a constant value. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Compound Division</title>

</head>
<body>

<h2>Compound Division</h2>

<%
Dim Value = 12.75

Response.Write("Value = ")
Response.Write(Value)

Value = Value / 2.42

Response.Write("<br>Value = ")
Response.Write(Value)
%>

</body>
</html>

This would produce:

Compound Division

A shortcut of this operation uses the /= operator. Here is an example of using it:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Compound Division</title>

</head>
<body>

<h2>Compound Division</h2>

<%
Dim Value = 12.75

Response.Write("Value = ")
Response.Write(Value)

Value /= 2.42

Response.Write("<br>Value = ")
Response.Write(Value)
%>

</body>
</html>

The Remainder

The remainder operation is usedt to get the value remaining after a division renders a natural result. The remainder operation is performed using the Mod operator. Its formula is:

value1 Mod value2

The result of the operation can be used as you see fit or you can display it in a control or be involved in another operation or expression.

As seen with the other arithmetic operators, you can find the remainder of a variable and assign the result to the variable itself. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head>
<title>Exercises</title>

</head>
<body>

<h2>Exercises</h2>

<%
Dim Players = 18

' When the game starts, how many players will wait?.
Response.Write("Out of ")
Response.Write(Players)
Response.Write(" players, ")

Players = Players Mod 11

Response.Write(Players)
Response.Write(" players will have to wait when the game starts.")
%>

</body>
</html>

This would produce:

The Compound Remainder


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