VBS : Tutorial 5 (Funtions )

VBS : Tutorial 5 (Funtions )

Functions

 

Example 1 :         Syntax

 

Call func_name

Function Func_name()

                msgbox 1+2

end function

 

 

Example 2:          Returning Value

msgbox func_name

 

Function func_name()

                func_name=1+2

end function

 

Example :Calculate age of a person

 

Dim sVar1

sVar1=inputbox("e.g.  1947 "," Please Enter Years")

msgbox fn(sVar1)

 

Function fn(x)

                fn= year(date)-x

End Function

 

 

Example 3:          Sub-routine

Call func_name

 

Sub Func_name()

                msgbox 1+2

end Sub

 

Example 4:          Function vs Sub

msgbox func_name

 

Sub Func_name()

                func_name = 1+2

end Sub

 

Example 5 :         Sending Values to Functions

 

Dim a,b

a=3

b=4

 

msgbox Add(a,b)

 

Function Add(x,y)

                Add=x+y

End Function

 

 

Example 6:          Sending arrays to function

 

Dim a(9)

Call Add(a)

 

Function Add(x)

                msgbox isarray(x)           

End Function

 

Example 7 :         Catching the Return Value  and Flags in framework

 

Dim a(9),bVar

bVar = Add(a)

msgbox  bVar

 

Function Add(x)

                Add=isarray(x) 

End Function

 

Example 8:          Function accept multiple arguements but returns only 1 value

 

Example 9:          Variables are Global Unless declared ,-----NOT DECLARED i.e., PASS BY REF

msgbox a

call fn

call fn2()

msgbox a

 

Function fn()

                a=5

                msgbox a

end function

 

Function fn2()

                msgbox a

                a="dfsdf"

                msgbox a

end function

 

Example 10: ---             DECLARED

msgbox a

call fn

call fn2()

msgbox a

 

Function fn()

                a=5

                msgbox a

end function

 

Function fn2()

                Dim a

                msgbox a

                a="dfsdf"

                msgbox a

end function

 

Example

dim a

a=10.5

msgbox a

call fn

call fn2()

msgbox a

 

Function fn()

dim a

                a=5

                msgbox a

end function

 

Function fn2()

dim a

                msgbox a

                a="piyush"

                msgbox a

end function

 

Example 9 :         Pass By Value and pass By Ref  , By Default --> ByRef

 

 

-------------------------------------------

By Default variables are passed ByRef

------------------------------------------

Ex Byval

 

Option Explicit

Dim strTest

 

strTest = "FOO"

RunTest (strTest)

msgbox  strTest

 

Sub RunTest(ByVal strIn)

                WScript.Echo strIn

                strIn = "BAR"

                msgbox strIn

End Sub

 

OUTPUT:

FOO

 BAR

 FOO

------------------------------------------------------

The default is ByRef. This stands for "By Reference"

any changes that you make inside the Sub/Function will be seen outside the Sub/Function. Here is a demonstration:

 

Option Explicit

 

Dim strTest

 

strTest = "FOO"

RunTest (strTest )

msgbox  strTest

 

Sub RunTest(strTest)

                WScript.Echo strTest

                strTest = "BAR"

                msgbox strTest

End Sub

 

OUTPUT: >>

FOO

 BAR

 BAR

 

Example 1:  Redim and preserve

Redim a(1,2)

Redim a(2,3)

 

Example 2

Redim preserve  a(1,2)

Redim a(2,3)