Decision making allows the programmers to control the execution flow of a script or one of its sections. The execution is governed by one or more conditional statements.
Following is the general form of a typical decision making structure found in most of programming languages.
VBA provides the following types of decision making statements.
| Sr.No. | Statement & Description |
|---|---|
| 1 | if statement An if statement consists of a Boolean expression followed by one or more statements. |
| 2 | if..else statement An if else statement consists of a Boolean expression followed by one or more statements. If the condition is True, the statements under If statements are executed. If the condition is false, the Else part of the script is executed. |
| 3 | if…elseif..else statement An if statement followed by one or more ElseIf statements, that consists of Boolean expressions and then followed by an optional else statement, which executes when all the condition become false. |
| 4 | nested if statements An if or elseif statement inside another if or elseif statement(s). |
| 5 | switch statement A switch statement allows a variable to be tested for equality against a list of values. |
VBA – If Statement
An If statement consists of a Boolean expression followed by one or more statements. If the condition is said to be True, the statements under If condition(s) are executed. If the condition is said to be False, the statements after the If loop are executed.
Syntax
Following is the syntax of an If statement in VBScript.
If(boolean_expression) Then Statement 1 ..... ..... Statement n End If
Flow Diagram
Example
For demo purposes, let us find the biggest between the two numbers of an Excel with the help of a function.
Private Sub if_demo_Click() Dim x As Integer Dim y As Integer x= 234 y = 32 If x > y Then MsgBox "X is Greater than Y" End If End Sub
When the above code is executed, it produces the following result.
X is Greater than Y
VBA – If-Else Statement
An If statement consists of a Boolean expression followed by one or more statements. If the condition is said to be True, the statements under If condition(s) are executed. If the condition is said to be False, the statements under Else Part is executed.
Syntax
Following is the syntax of an If Else statement in VBScript.
If(boolean_expression) Then Statement 1 ..... ..... Statement n Else Statement 1 ..... .... Statement n End If
Flow Diagram
Example
For demo purpose, let us find the biggest between the two numbers of an Excel with the help of a function.
Private Sub if_demo_Click() Dim x As Integer Dim y As Integer x = 234 y = 324 If x > y Then MsgBox "X is Greater than Y" Else Msgbox "Y is Greater than X" End If End Sub
When the above code is executed, it produces the following result.
Y is Greater than X
VBA – If Elseif – Else statement
An If statement followed by one or more ElseIf statements that consist of boolean expressions and then followed by a default else statement, which executes when all the condition becomes false.
Syntax
Following is the syntax of an If Elseif – Else statement in VBScript.
If(boolean_expression) Then Statement 1 ..... ..... Statement n ElseIf (boolean_expression) Then Statement 1 ..... .... Statement n ElseIf (boolean_expression) Then Statement 1 ..... .... Statement n Else Statement 1 ..... .... Statement n End If
Flow Diagram
Example
For demo purpose, let us find the biggest between the two numbers of Excel with the help of a function.
Private Sub if_demo_Click() Dim x As Integer Dim y As Integer x = 234 y = 234 If x > y Then MsgBox "X is Greater than Y" ElseIf y > x Then Msgbox "Y is Greater than X" Else Msgbox "X and Y are EQUAL" End If End Sub
When the above code is executed, it produces the following result.
X and Y are EQUAL
VBA – Nested If Statement
An If or ElseIf statement inside another If or ElseIf statement(s). The inner If statements are executed based on the outermost If statements. This enables VBScript to handle complex conditions with ease.
Syntax
Following is the syntax of an Nested If statement in VBScript.
If(boolean_expression) Then
Statement 1
.....
.....
Statement n
If(boolean_expression) Then
Statement 1
.....
.....
Statement n
ElseIf (boolean_expression) Then
Statement 1
.....
....
Statement n
Else
Statement 1
.....
....
Statement n
End If
Else
Statement 1
.....
....
Statement n
End If Example
For demo purposes, let us find the type of a positive number with the help of a function.
Private Sub nested_if_demo_Click() Dim a As Integer a = 23 If a > Then MsgBox "The Number is a POSITIVE Number" If a = 1 Then MsgBox "The Number is Neither Prime NOR Composite" ElseIf a = 2 Then MsgBox "The Number is the Only Even Prime Number" ElseIf a = 3 Then MsgBox "The Number is the Least Odd Prime Number" Else MsgBox "The Number is NOT 0,1,2 or 3" End If ElseIf a < Then MsgBox "The Number is a NEGATIVE Number" Else MsgBox "The Number is ZERO" End If End Sub
When the above code is executed, it produces the following result.
The Number is a POSITIVE Number The Number is NOT 0,1,2 or 3
VBA – Switch Statement
When a user wants to execute a group of statements depending upon a value of an Expression, then Switch Case is used. Each value is called a Case, and the variable is being switched ON based on each case. Case Else statement is executed if the test expression doesn’t match any of the Case specified by the user.
Case Else is an optional statement within Select Case, however, it is a good programming practice to always have a Case Else statement.
Syntax
Following is the syntax of a Switch statement in VBScript.
Select Case expression
Case expressionlist1
statement1
statement2
....
....
statement1n
Case expressionlist2
statement1
statement2
....
....
Case expressionlistn
statement1
statement2
....
....
Case Else
elsestatement1
elsestatement2
....
....
End Select Example
For demo purpose, let us find the type of integer with the help of a function.
Private Sub switch_demo_Click() Dim MyVar As Integer MyVar = 1 Select Case MyVar Case 1 MsgBox "The Number is the Least Composite Number" Case 2 MsgBox "The Number is the only Even Prime Number" Case 3 MsgBox "The Number is the Least Odd Prime Number" Case Else MsgBox "Unknown Number" End Select End Sub
When the above code is executed, it produces the following result.
The Number is the Least Composite Number
