The grouping of the lines of code to execute it "repeatedly" , can be broadly classified as Procedures. In QTP/UFT, we have two different types of procedures – Sub Procedures and Functions. Both of them work the same way expect for some minor differences.
Executing a Procedure in QTP/UFT.
Any Procedure (Function/Sub) in VBScript has two main aspects which are mandatory for executing it in VBScript. These are -
- Function (Sub) Definition or Declaration: Function Definition is the actual code that you want to run as part of the function
- Function Call: This is a statement which executes your Function or Sub
Let’s see an example of this where we would create a function to find the sum of two numbers and display the result.
Sample Code 1: Structure of a Procedure (Function & Sub)
'Structure for Sub
'====================
'1) Sub Definition - Actual Code
Sub fnSum()
var1 = 5 : var2 = 10
sum = var1 + var2
msgbox "The Sum of Numbers is: " & sum
End Sub
'2) Executing Sub
Call fnSum() 'Call keyword is not mandatory to execute a Sub
fnSum()
'Structure for Function
'======================
'1) Function Definition - Actual Code
Function fnSum()
var1 = 5 : var2 = 10
sum = var1 + var2
msgbox "The Sum of Numbers is: " & sum
End Function
'2) Executing Function
Call fnSum() 'Call keyword is not mandatory to execute a Function
fnSum()
In the above example you can see that Call statement can also be used while calling a function/sub.
Subs in QTP/UFT
A Sub Procedure in QTP/UFT -
- - is a collection of statements that are enclosed between Sub and End Substatements.
- - can be used both with and without parameters.
- - does not return any value.
Passing Parameters in a Sub Procedure
Consider a situation where you want to run the same set of code multiple times but with different set of data. In such a case, you can pass the data to your Sub in the form of parameters. This way you can make the code generic which can work with multiple set of data. Let’s see an example for the same.
Sample Code 2: Using Parameters in a Sub
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Dim v1, v2
v1=5 : v2=10
fnSum v1, v2
fnSum 10, 20
fnSum v1+10, v2*2
Sub fnSum(var1, var2)
sum = var1 + var2
msgbox "The sum of numbers is: " & sum
End Sub
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Functions in QTP/UFT:
A Function in QTP/UFT -
- - is a set of statements that are enclosed between Function and End Functionstatements.
- - can be used with and without parameters
- - can return a value.
The difference between a function and a sub is that a function can return a value, but a sub can’t return any value.
Passing Parameters in a Function
You can pass parameters in a function the same way it’s done for a sub. Let’s see an example for this.
Sample Code 3: Using Parameters in a Function
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Dim v1, v2
v1=5 : v2=10
fnSum v1, v2
fnSum 10, 20
fnSum v1+10, v2*2
Function fnSum(var1, var2)
sum = var1 + var2
msgbox "The sum of numbers is: " & sum
End Function
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Returning a value from a Function in QTP
One additional advantage that Functions have over Sub is that a Function can return a value. To return a value from a function, we need to take care of the following two things -
- 1) To return a value from a function, you need to use the statementfunctionName = ReturnValue, where functionName is the actual name of the function and ReturnValue is the value you want to return.
- 2) To capture the returned value, you need to use the statement someVariable =functionName() while calling the function.
Let’s understand this with the help of an example.
Sample Code 4: Returning value from a Function
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Dim result
result = fnSum(10, 20)
msgbox "The sum of the numbers is: " & result
Function fnSum(var1, var2)
sum = var1 + var2
fnSum = sum
End Function
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Passing Parameters to a Function/Sub – Pass By Value & Pass By Reference
You can pass parameters to a function or sub procedure by value or by reference. Let’s see what both these terms mean.
Passing Parameters by Value (byVal). With this way of passing parameters, only a copy of the original parameters is passed. This means that whatever modifications we make to the parameters inside the function, it doesn’t affect the original parameters.
Sample Code 5: Passing parameters by value to a function
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Dim val
val=5
fnFunc val
msgbox "Original Value: " & val
Function fnFunc(byVal val)
val = val + 2
msgbox "New Value: " & val
End Function
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In the above example you would see that the new value get changed to 7 but it doesn’t get reflected to the original value which still shows the value as 5 only.
Passing Parameters by Reference (byRef). In this case, the reference of the original value is passed as the parameter to the function. Therefore, whatever change is done to the parameter inside the function, the same is reflected in the original parameter also. By default, values are passed by reference in a function. i.e., even if you don’t use byRef keyword, the parameters are passed by reference.
Sample Code 6: Passing parameters by reference to a function
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Dim val
val=5
fnFunc val
msgbox "Original Value: " & val
Function fnFunc( ByRef val)
val = val + 2
msgbox "New Value: " & val 'msgbox displays value 7
End Function
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Since the original parameter is passed as reference to the function, both the original and new value has the updated value 7.