VB Script (Beginners) (II)

VB Script (Beginners) (II)

Conditional ConstructsIn VBScript we have four conditional statements:

if statement - use this statement if you want to execute a set of code when a condition is true

if...then...else statement - use this statement if you want to select one of two sets of lines to execute

if...then...elseif statement - use this statement if you want to select one of many sets of lines to execute

select case statement - use this statement if you want to select one of many sets of lines to execute

If....Then.....Else

You should use the If...Then...Else statement if you want to execute some code if a condition is true

For example: if i=10 Then msgbox "Hello"

If you want to execute more than one statement when a condition is true, you must put each statement on separate lines and end the statement with the keyword "End If"

For Example:

If i = 10 Then

msgbox “POOJA”

i = i+1

end If

(Here you are telling the code to perform multiple actions if the condition is true)

To execute a statement if a condition is true and execute another statement if the condition is not true, you must add the "Else" keyword.

If i = 10 Then

msgbox “Hello Pooja”

else

msgbox “Goodbye Pooja”

end If

If....Then.....Elseif

You can use the if...then...elseif statement if you want to select one of many blocks of code to execute:

if payment="Electricity Bill" then

msgbox "You are going to pay Electricity Bill!"

elseif payment="Telephone bill" then

msgbox "You are going to pay Telephone Bill।"

elseif payment="Gas Bill" then

msgbox "You are going to pay Gas Bill।"

Else

msgbox "Other Bill Option।"

end If

Select Case

You can also use the SELECT statement if you want to select one of many blocks of code to execute:

select case Bill

case "Electricity Bill"

msgbox "You are going to pay Electricity Bill"

case "Telephone Bill"

msgbox "You are going to pay Telephone Bill"

case "Gas Bill"

msgbox "You are going to pay Gas Bill"

case Else

msgbox "Other Bill Options"

end select Looping Statements

In VBScript we have four looping statements: For...Next statement - runs statements a specified number of times.

For Each...Next statement - runs statements for each item in a collection or each element of an array

Do...Loop statement - loops while or until a condition is true

While...Wend statement - Do not use it - use the Do...Loop statement instead

For...Next statement

For i=1 to 10

some code

Next

The For statement specifies the counter variable (i) and its start and end values। The Next statement increases the counter variable (i) by one.

Step Keyword Using the Step keyword, you can increase or decrease the counter variable by the value you specify.

For i=2 To 10 Step 2

some code

Next

To decrease the counter variable, you must use a negative Step value

For i=10 To 2 Step -2

some code

Next

For Each...Next Loop

A For Each...Next loop repeats a block of code for each item in a collection, or for each element of an array.

dim cars(2)

cars(0)="Volvo"

cars(1)="Saab"

cars(2)="BMW"

For Each x in cars document.write(x & " ")

Next

Do...Loop

You can use Do...Loop statements to run a block of code when you do not know how many repetitions you want.

Repeating Code While a Condition is True

You use the While keyword to check a condition in a Do...Loop statement.

Do While i>10

some code ----> If i equals 9, the code inside the

loop loop above will never be executed.

Notice the difference between the two examples.

Do

some code ----> Code inside the loop will be executed Loop While i>10 at least one time even if i is lessthan 10.

Exit a Do...Loop

Do Until i=10

i=i-1

If i<10>Then Exit Do

Loop

EX: dim names(2)

arrays are of two types à Local Arrays And Global Arrays

=>Local array is available only within the function or procedure, where it is declared

=> global array is an array that can be used by all functions and procedures. It is declared at the beginning of the VBScript Code.

TheDim statement is used to declare arrays।

The syntax for declaring an array is as follows:

Dim ArrayName(subscriptvalue)

=>ArrayName is the unique name for the array

=>SubscriptValue is a numeric value that indicates the number of elements in the array dimension within the array

Example:

Dim No_Passengers(3)

Note:The No_Passengers can store 4 values। Assigning values to the array

No_Passengers(0) = 1

No_Passengers(1) = 2

No_Passengers(2) = 3

No_Passengers(3) = 4

Static and Dynamic Arrays:

Static Array--- The size of a static array cannot be altered at run time.

Dynamic Array --- A dynamic array can be resized at any time. The array size can be changed at run time.