You will use If – Then statements often. The general form of the statement is:
If condition Then true_instructions [Else false_instructions]
The following program will prompt you with an Input Box for a number between 1 and 10. If the number is greater than 5, print Watch late news. Otherwise print Watch morning news.
Note: The If statement does not fit on one line. By placing a space and underscore at the end of the line, you can continue the text to the next line.
Notice the third line. The InputBox has the form: InputBox (“Prompt text”). The variable number is set equal to the value you type into the InputBox.
Sub Test8()
Dim number As Long
number = InputBox (“Enter a number between 1 and 10.”)
If number > 5 Then MsgBox “Watch late news.”
_
Else MsgBox “Watch morning news.”
End Sub
Sometimes a very short If – Then statement is useful. It takes the form:
If condition Then true-instructions
The following program will prompt you with an InputBox for a number between 1 and 10. If the number is greater than 5 then the message box prints Watch late news. Otherwise, you go to End Sub.
Sub Test9()
Dim number As Long
number = InputBox (“Enter a number between 1 and 10.”)
If number > 5 Then MsgBox “Watch late news.”
End Sub
This construct makes use of nested If statements. It takes the general form:
If condition Then
statement
Else
If condition Then
statement
Else
If condition Then
statement
End If
End If
End If
In the next subroutine an InputBox will ask you to enter a number between 1 and 10. If the number is less than 3 then a message box will say Watch morning news. If the number is equal to 3 then a message box will say Watch noon news. If the number is greater than 3 then a message box will say Watch late news.
Sub Test10()
Dim number As Long
number = InputBox (“Enter a number between 1 and 10.”)
If number < 3 Then
MsgBox “Watch morning news.”
Else
If number = 3 Then
MsgBox “Watch noon news.”
Else
If number > 3 Then
MsgBox “Watch late news.”
End If
End If
End if
End Sub
The If-ElseIf-Else structure exists because it is more efficient. In our preceding examples of If statements all the statements are read. In the If-ElseIf-Else structure the computer stops reading conditions when a true condition is met.
It takes the general form:
If condition Then
true_instructions
ElseIf condition Then
alternate_instructions
Else
alternate_instructions
End If
The program below duplicates the results of the Nested If – Then – Else program.
Sub Test11()
Dim number As Long
number = InputBox (“Enter a number between 1 and 10.”)
If number < 3 Then
MsgBox “Watch morning news.”
ElseIf number = 3 Then
MsgBox “Watch noon news.”
Else
MsgBox “Watch late news.”
End If
End Sub
A Select Case statement does not have If in it, but it acts like a nested If statement.
The Select Case statement is a third way of executing the program above. It is useful for choosing between three or more options.
It takes the following general form:
Select Case test_expression
Case Is test_expression condition
instruction statement
Case Is test_expression condition
instruction statement
Case Is test_expression condition
instruction statement
Case Is test_expression condition
instruction statement
End Select
The following program repeats the results of the two programs above.
Sub Test12()
Dim number As Long
number = InputBox (“Enter a number between 1 and 10.”)
Select Case number
Case Is < 3
MsgBox “Watch morning news.”
Case Is = 3
MsgBox “Watch noon news.”
Case Is > 3
MsgBox “Watch late news.”
End Select
End Sub
Table of Contents
Ch1-Introduction
Ch2-Loops
Ch3-If Statements
Ch4-Functions
Ch5-Subs & Functions
Ch6-Read & Write
Ch7-Operators
Ch8-Built-in Functions
Ch9-Built-in Examples
Ch10-Debugging
Ch11-Running Subs
Ch12-Sample Programs
Ch13-WS Formulas
Ch14-Questions
