VB Script - Part III
Control Flow Functions
⇒Do...Loop Statement
Do...Loop: Repeats a block of statements while a condition is True or until a condition becomes True.
⇒Do...Loop Statement
Do...Loop: Repeats a block of statements while a condition is True or until a condition becomes True.
Syntax:
Do [{While | Until} condition]
[statements]
[Exit Do]
[statements]
Loop
OR
Do
[statements]
[Exit Do]
[statements]
Loop [{While | Until} condition]
Arguments:
| condition: | Numeric or string expression that is True or False. If condition is Null, condition is treated as False. |
| statements: | One or more statements that are repeated while or until condition is True. |
Example:
'Do...Loop Counter = 1 Do While Counter < 4 Total =Inputbox("Please enter the total marks in numbers") If Total < 50 Then MsgBox "Fail" ElseIf Total >=50 and Total <=60 then Msgbox "Second Class" ElseIf Total >60 and Total <80 then Msgbox "First Class" ElseIf Total >=80 then Msgbox "Distinction" Else Msgbox "Invalid Marks" End If Counter = Counter + 1 Loop
Example:
Counter = 1
Do
Total =Inputbox("Please enter the total marks in numbers")
If Total < 50 Then
MsgBox "Fail"
ElseIf Total >=50 and Total <=60 then
Msgbox "Second Class"
ElseIf Total >60 and Total <80 then
Msgbox "First Class"
ElseIf Total >=80 then
Msgbox "Distinction"
Else
Msgbox "Invalid Marks"
End If
Counter = Counter + 1
Loop until Counter > 4
Example:
'Exit Do While loop Do While Counter < 10 Counter=counter + 1 If counter = 6 Then Exit Do End If Print Counter Loop
Example:
'Exit Do Until loop Do Counter=Counter + 1 If Counter = 6 Then Exit Do End If Print Counter Loop Until counter >11
⇒For...Next Statement
For...Next: Repeats a group of statements a specified number of times.
Syntax:
For counter = start To end [Step step]
[statements]
[Exit For]
[statements]
Next
Arguments:
| counter: | Numeric variable used as a loop counter. The variable can't be an array element or an element of a user-defined type. |
| start: | Initial value of counter. |
| end: | Final value of counter. |
| step: | Amount counter is changed each time through the loop. If not specified, step defaults to one. |
| statements: | One or more statements between For and Next that are executed the specified number of times. |
Example:
For...Next Counter = 1 For Counter = 1 to 4 Total =Inputbox("Please enter the total marks in numbers") If Total < 50 Then MsgBox "Fail" ElseIf Total >=50 and Total <=60 then Msgbox "Second Class" ElseIf Total >60 and Total <80 then Msgbox "First Class" ElseIf Total >=80 then Msgbox "Distinction" Else Msgbox "Invalid Marks" End If Next
Example:
' increment loop by 3 Counter = 1 Result = 0 For Counter = 1 to 10 step 3 Result=Result + Counter Print Result Next
Example:
'Decrement loop by 2 For Counter = 10 to 1 step -2 Print Counter Next
Example:
'Exit For Loop For Counter=1 to 10 If Counter=6 Then Exit for End If Print Counter Next
⇒For Each...Next Statement
For Each...Next: Repeats a group of statements for each element in an array or collection.
Syntax:
For Each element In group
[statements]
[Exit For]
[statements]
Next [element]
Arguments:
| element: | Variable used to iterate through the elements of the collection or array. For collections, element can only be a Variant Variable, a generic Object variable, or any specific Automation object variable. For arrays, element can only be a Variant variable. |
| group: | Name of an object collection or array. |
| statements: | One or more statements that are executed on each item in group. |
⇒If...Then...Else Statement
If...Then...Else: Conditionally executes a group of statements, depending on the value of an expression.
Syntax:
If condition Then statements [Else elsestatements ]
OR
If condition Then
[statements]
[ElseIf condition-n Then
[elseifstatements]] . . .
[Else
[elsestatements]]
End If
Arguments:
| condition: | One or more of the following two types of expressions:
A numeric or string expression that evaluates to True or False. If condition is Null, condition is treated as False.
An expression of the form Type of objectname Is object type. The object name is any object reference and object typeis any valid object type. The expression is True if object name is of the object type specified by object type; otherwise it is False.
|
| statements: | One or more statements separated by colons; executed if condition is True. |
| condition-n: | Same as condition. |
| elseifstatements: | One or more statements executed if the associated condition-n is True. |
| elsestatements: | One or more statements executed if no previous condition or condition-n expression is True. |
Example:
Example:
'If...Then...Else Total = Inputbox("Please enter the total marks in number ") If Total >= 50 Then MsgBox "Pass" Else Msgbox "Fail" End If
Example:
'If....ElseIf Total = Inputbox("Please enter the total marks in number") If Total < 50 Then MsgBox "Fail" ElseIf Total >=50 and Total <=60 then Msgbox "Second Class" ElseIf Total >60 and Total <80 then Msgbox "First Class" ElseIf Total >=80 then Msgbox "Distinction" Else Msgbox "Invalid Marks" End If
⇒Select Case statement
Select Case: Executes one of several groups of statements, depending on the value of an expression.
Syntax:
Select Case testexpression
[Case expressionlist-n
[statements-n]] . . .
[Case Else expressionlist-n
[elsestatements-n]]
End Select
Arguments:
| testexpression: | Any numeric or string expression. |
| expressionlist-n: | Required if Case appears. Delimited list of one or more expressions. |
| statements-n: | One or more statements executed if testexpression matches any part of expressionlist-n. |
| elsestatements-n: | One or more statements executed if testexpression doesn't match any of the Case clauses. |
Example:
⇒While...Wend statement
Example:
⇒With statement
'Select Case Colour =Ucase( Inputbox("Please enter the colour of your choice")) Select Case Colour Case "RED" MsgBox "Colour selected is Red" Case "BLUE" MsgBox "Colour selected is Red" Case "GREEN" MsgBox "Colour selected is Red" Case ELSE MsgBox "Invalid Colour" End Select
⇒While...Wend statement
While...Wend: Executes a series of statements as long as a given condition is True.
Syntax:
While condition
Version [statements]
Wend
Arguments:
| condition: | Numeric or string expression that evaluates to True or False. If condition is Null, condition is treated as False. |
| statements: | One or more statements executed while condition is True. |
Example:
'While...Wend Counter =1 While Counter < 4 Total =Inputbox("Please enter the total marks in numbers") If Total < 50 Then MsgBox "Fail" ElseIf Total >=50 and Total <=60 then Msgbox "Second Class" ElseIf Total >60 and Total <80 then Msgbox "First Class" ElseIf Total >=80 then Msgbox "Distinction" Else Msgbox "Invalid Marks" End If Counter=counter + 1 Wend
⇒With statement
With: Executes a series of statements on a single object.
Syntax:
With object
statements
End With
Arguments:
| object: | Required. Name of an object or a function that returns an object. |
| statements: | Required. One or more statements to be executed on object. |
Comments
Post a Comment