Selection
|
Selection |
This statement is used to select statements based upon testing an expression. If the expression is TRUE, certain statements can be run, whilst the expression is FALSE, different statements can be run.
| Syntax | Explanation |
| If
expression Then
statements End If |
If expression is TRUE, then statements are executed, otherwise do nothing |
| If
expression Then
statements1 Else statements2 End If |
If expression is TRUE, then statements1 are executed, otherwise if expression is FALSE then execute statements2 |
| The previous IF limited you to testing one expression. By adding ElseIf, you can test as many expressions as you want, although a Case statement would be more efficient: | |
| If expression1
Then
statements1 ElseIf expression2 Then statements2 Else statements3 End If |
If expression1 is TRUE,
then statements1 are executed.
If expression2 is TRUE then statements2 are executed. If expression1 AND expression2 are FALSE then statements3 are executed |
| Examples | |
| If Score
>= MathsPassRate Then
Msgbox "Student Passed Maths" End If |
|
| If Score
>= MathsPassRate Then
Msgbox "Student Passed Maths" Else Msgbox "Student Failed Maths" End If |
|
| If Age =
18 Then
Msgbox "Just old enough to drink alcohol" ElseIf Age > 18 Then Msgbox "Old enough to drink alcohol" Else Msgbox "Too young enough to drink alcohol" End If |
|
Case statements should be used when testing a variable which may result in more than two outcomes.
| Syntax | Explanation |
| Select Case variable
Case expression1 statements1 Case expression2 statements2 ..... Case expressionN statementsN Case Else statementsElse End Select |
Note: each expression is
testing the variable stated as part of Select Case...
If expression1 is TRUE, statements1 are executed. All other statements are bipassed.
If expression2 is TRUE, statements2 are executed and so on.
If none of the above expressions are true, the statementsElse are executed. |
Examples |
Select Case Month
End Select |
Select Case Mark
|
| Non-continuous range: |
Select Case Month
End Select |
Select Case Subject
End Select |