If Statement
It is very common to test a condition and take either of two
possible actions based on the result of the test. If statement is used to test condition and act according to the
result of the condition.
If condition Then
Statements
Else
Statements
End if
If condition is
satisfied then statements given after Then
will be executed otherwise statements given after Else are executed.
As you can understand from the syntax, Else is optional. If you do not give else then no statements will
be executed when condition is not true.
Single Line vs. Multiple Line
You can give entire if
statement in a single line. The following is an example of single line if statements.
If amount > 10000 then discount = amount * 0.10
Note that when you use single
line if statement End if is NOT
required.
If .. then .. elseif… else statement
When you have to test for multiple conditions and take
action based on the result of conditions then multiple if statement is best
suited.
If condition then
Statements
Elseif
condition then
Statements
Else
Statements
End if
In the if..elseif ladder,
if condition is ever true the statements after that conditions will be executed
and control comes out of entire if statement.
The following is an example where we determine the
percentage of discount based on the value of amount variable.
If amount > 20000 then
Dis = 10
Elseif amount > 15000
then
Dis = 8
Elseif amount > 10000 then
Dis = 5
Else
Dis = 0 ‘ no discount
End if
Select Case Statement
This statement is used when a
single variable value is to be compared with different set of values.
Select
Case expression
Case value-1
Statements
[Case value-2
Statements]…
[Case else
Statements]
End
Select
Expression is
evaluated in the beginning of the statement and the result is compared with the
given values from top. If at any point the value is equivalent to the result of
condition then the corresponding statements are executed and control comes out
of Select Case statement.
Case Else is
executed when none of the given values match the result of the expression.
The value may be either a single value or a range of values
or a collection of values. It may also be a combination of all. The following
example will explain the point.
Select Case code
Case 1
Dis = 10
Case 2 to 4
Dis = 12
Case 5, 7
Dis = 14
Case 6, 7 to 10
Dis = 11
Case else
Dis = 0
End select
In the above Select
Case statement, first the value of variable code is compared with 1 (first case). If they are same then the
corresponding action takes place (setting dis
variable to value 10). Otherwise, code is
compared with second case, in which case, condition will be true if code is in the range 2 to 4. In third
case code is compared with 5 and 7.
In fourth case, code is compared
with value 6 and also with the range from 7 to 10.
In none of the given conditions are true, then statements
given after Case Else are executed,
where dis is set to 0. The following
are the possible values that you can give after each case:
¨
A single constant. Ex: 10
¨
A single range. Ex: 1 to 5
¨
A collection of values each separated by comma.
Ex: 1,4,6
¨
Any combination of the above three. Ex: 5,7, 10
to 15
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