Thursday, January 3, 2019


Simple Functions in VBScript

Functions in VBScript
Functions are used to perform the specific task.Functions are used to increase the reusability of the code. Functions are similar to the procedures except one difference that functions can return value.

Simple example of the function


Suppose you want to find the sum of 2 numbers. Without functions, you will write below code.

a = 10
b = 20
c = a+ b
Msgbox c

To add another 2 different numbers, you will use below code

a = 33
b = 65
c = a+ b
Msgbox c

In above examples, we have to add 2 numbers. So the operation is same (Repeating) So we can write the function which will take 2 parameters as shown below.

function sum(byref a, byref b)
sum = cint(a) + cint(b)
end function

Calling functions in VBScript

To call the procedures we can use below statements.

c = sum(10,20)
msgbox c
c = sum(33,65)
msgbox c

Thus we can call functions many times in the code. This reduces the lines of code  as well as maintainability of the code.

Passing arguments to the function

We can pass the arguments to the function by 2 ways.
  1. Pass by reference 
  2. Pass by value
Pass by reference

By default, values are passed to the function by reference. When we pass the values by reference the changes made to the variables in the called function are reflected in the calling function/procedure.

a = 10
c = findsqr(a)
msgbox a 'prints 100
msgbox c 'prints 100
function findsqr(byref a)
a = a*a
findsqr = a
end function


Pass by value

When we pass the values by value, the changes made to the variables in the called function are not reflected in the calling procedure or function.

a = 10
c = findsqr(a)
msgbox a 'prints 10
msgbox c 'prints 100
function findsqr(byval a)
a = a*a
findsqr = a
end function

Other built-in functions in VBScript

  1. msgbox
  2. inputbox
  3. eval 
  4. execute
msgbox function is used to show message to the user.
inputbox function is used to read the value from the user.

a = inputbox("Enter the number")
msgbox a 'prints 33

Inputbox function in vbscript
Eval and execute functions are used to execute any valid vbscript expression. Difference between 2 functions is that the operator = is handled in different ways.

Eval always uses = as a comparison operator.
Execute always uses = as a assignment operator.

Example -
a=20
msgbox eval("a=10") 'will print false
msgbox a
a=20
execute("a=10")
msgbox a 'will print 10


Related Posts:

  • File system object in vb script File system object in vb script Filesystemobject can be used to work with drives, folders, and files.Filesystemobject  has methods and properties that allow us to create, delete, gain information about, and gener… Read More
  • What is Windows Script Host? What is Windows Script Host? WSH is a scripting host for Windows Script compatible scripting engines.WSH supports various scripting languages like vbscript, javascript, python etc.You can do below operations using WSH… Read More
  • What is WMI? What is WMI?  WMI and Win32 classes WMI stands for Windows Management Instrumentation. This is used to access system hardware and software features. It provides very powerful API to perform tasks like starting pr… Read More
  • Dictionary Object in vb script Example Dictionary Object in vb script Example Dictionary object is used to store the data in key-item pairs in qtp.A Dictionary object is just like an associative array.It stores the data in the form of key-item pairs.Each k… Read More
  • Error handling in VBScript Error handling in VBScript VBScript provides below statements and keywords to handle errors. on error resume next Err object - err.description, err.number Sample code to handle the error is given below If er… Read More

0 comments:

Post a Comment

Blog Archive

Translate

Popular Posts

Total Pageviews

151,972

Blog Archive