1. 4a- If And Else Lingma Acheson CSCI N331 VB .NET Programming
Department of Computer and Information Science, IUPUI

2. If Statement
Sometimes we want things to happen only when a certain condition is met, e.g. in the Calculator project, only perform the division when the second input is not 0.
Structure:
If condition1 Then
statement1
statement2 …
End If
Meaning: If condition1 is true, statements will be executed, otherwise, nothing happens.
E.g. If dblInput2 <> 0 Then
dblResult = dblInput1 / dblInput2

3. If/Else Statement
Sometimes we want to say “If condition1 is true, do this, otherwise, do that.” E.g. If the second input is not 0, perform the division, otherwise, telling the user “The second number is 0, unable to perform the division.”
Structure:
If condition1 Then
statement1
statement2
Else
statement3
statement4
End If
If condition1 is true, statement1 and statement2 will be executed, otherwise, statement3 and statement4 will be executed.

4. If/Else Statement End If E.g. If dblInput2 <>0 Then
dblResult = dblInput1 / dblInput2
Else
MessageBox.Show(“The second input is 0, unable to perform the division.”)
End If

5. If/Else Statement Comparison operators:
=, <>, <, >, <=, >=