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Use branching statements to restrict the execution of a code block until a particular condition is satisfied.

== <tt>If...Then...Else</tt> ==

The most common branching statement is the <tt>If</tt> statement as shown in the following example:

<source lang="oobas">
If A > 3 Then
B = 2
End If
</source>

The <tt>B = 2</tt> assignment only occurs when value of variable <tt>A</tt> is greater than three. A variation of the <tt>If</tt> statement is the <tt>If/Else</tt> clause:

<source lang="oobas">
If A > 3 Then
B = 2
Else
B = 0
End If
</source>

In this example, the variable <tt>B</tt> is assigned the value of 2 when <tt>A</tt> is greater than 3, otherwise <tt>B</tt> is assigned the value of 0.

For more complex statements, you can cascade the <tt>If</tt> statement, for example:

<source lang="oobas">
If A = 0 Then
B = 0
ElseIf A < 3 Then
B = 1
Else
B = 2
End If
</source>

If the value of variable <tt>A</tt> equals zero, <tt>B</tt> is assigned the value 0. If <tt>A</tt> is less than 3 (but not equal to zero), then <tt>B</tt> is assigned the value 1. In all other instances (that is, if <tt>A</tt> is greater than or equal to 3), <tt>B</tt> is assigned the value 2.

A complete If statement may be written on a single line, with a simpler syntax. The first example of this page may be written as:

<source lang="oobas">
If A > 3 Then B = 2
</source>
The second example of this page may be written as:
<source lang="oobas">
If A > 3 Then B = 2 Else B = 0
</source>

== <tt>Select...Case</tt> ==

The <tt>Select...Case</tt> instruction is an alternative to the cascaded <tt>If</tt> statement and is used when you need to check a value against various conditions:

<source lang="oobas">
Select Case DayOfWeek
Case 1:
NameOfWeekday = "Sunday"
Case 2:
NameOfWeekday = "Monday"
Case 3:
NameOfWeekday = "Tuesday"
Case 4:
NameOfWeekday = "Wednesday"
Case 5:
NameOfWeekday = "Thursday"
Case 6:
NameOfWeekday = "Friday"
Case 7:
NameOfWeekday = "Saturday"
End Select
</source>

In this example, the name of a weekday corresponds to a number, so that the <tt>DayOfWeek</tt> variable is assigned the value of 1 for <tt>Sunday</tt>, 2 for <tt>Monday</tt> value, and so on.

The <tt>Select</tt> command is not restricted to simple 1:1 assignments — you can also specify comparison operators or lists of expressions in a <tt>Case</tt> branch. The following example lists the most important syntax variants:

<source lang="oobas">
Select Case Var
Case 1 To 5
' ... Var is between the numbers 1 and 5 (including the values 1 and 5).
Case > 100
' ... Var is greater than 100
Case 6, 7, 8
' ... Var is 6, 7 or 8
Case 6, 7, 8, > 15, < 0
' ... Var is 6, 7, 8, greater than 15, or less than 0
Case Else
' ... all other instances
End Select
</source>

Now consider a misleading (advanced) example, and a common error:

<source lang="oobas">
Select Case Var
Case Var = 8
' ... Var is 0
Case Else
' ... all other instances
End Select
</source>

The statement (Var = 8) evaluates to TRUE if Var is 8, and FALSE otherwise. TRUE is -1 and FALSE is 0. The Select Case statement evaluates the expression, which is TRUE or FALSE, and then compares that value to Var. When Var is 0, there is a match. If you understand the last example, then you also know why this example does not do what it appears

<source lang="oobas">
Select Case Var
Case Var > 8 And Var < 11
' ... Var is 0
Case Else
' ... all other instances
End Select
</source>

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