Control Flow in VBScript or UFT

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Control Flow in VBScript or UFT

This post talks about control flow statements in VBScript, control flow statements in UFT, control flow in VBScript, control flow in UFT. We can control the flow of our script with conditional statements and looping statements. Using conditional statements, we can write VBScript code that makes decisions and repeats actions.

Flow control in VB  script
The order of execution is known as flow in VB script. The flow gets executed top to bottom, in a sequential way and keep executing it until the end reaches.

Control of flow in VBScript or UFT

The logic that allows us to manipulate the execution of the code in our script is called control flow.

Control flow is divided into below section

1. Branching/comparison statements

This branching statement provides scripts with intelligence. Expressions/ conditions are the ones to be tested to get a True/ False outcome.VB script supports if else, endif, select branching is a technique by which depending on some condition few statements gets executed and some are not.

1.1- if end if

1.2— if else endif

1.3– select case

2. Looping

Looping is a technique which allows us to execute the same lines of code or block of code over and over until loop condition terminates it.

The loop is useful when
  • We want to repeat a block of code until termination condition(typically a Boolean condition yields true or false.)
  • We want to repeat a block of code for a predefined finite number of times.

2.1– For next[ for a predefined number of times]

2.2– Do while loop[ for a specific condition is true]

2.3– Do loop until[for a specific condition to be true]

2.4– For each next[For Each…Next Iterates through properties of an object ]

2.5—Do loop while [for a specific condition to be true]

2.6– Do until loop[for a specific condition to be true]

2.7– While -Wend

Comparison statements allow us to perform conditional logic tests between two expressions or values.

Note – It is always better to write start and end block of branching and looping before actual code block implementation.

Space or  White space is used for human consumption of the code. If we do not provide space machine can still understand the code. In that case, human readability will go down.

General indentation rule is to provide white spaces if the next line is a subcode of the above code.
If( condition) then
---- do something
---- do something
---- do something
end if
it will visually suggest the coding structure.

Select case— it is upgraded version of multiple if–else statements. It provides an output based on a list of possible matching expressions.

Dim userNumber
Dim reply
userName=  Inputbox("Enter your number")
reply= "the number is "& userNumber."
msgbox reply

if the user does not put any value still the message box is going to display” the number is” string and userNumber is blank hence it won’t print anything.

A better approach
dim userNumber
dim reply
userNumber= Inputbox(" enter your number")
If(userNumber="") Then
reply="Please put some number"
msgbox reply
else
reply="your number is"&userNumber
msgbox reply
End if

Details of If in VBScript or UFT

If — it compares two expressions or values and either perform some set of statements or skip some statements. Also If tests the expression then keyword execute the true condition execute true condition else executes the false part.

if [expression] Then 
Statements 
End if

If works on boolean value hence all the expression used in if condition must boolean output. The code resides inside if- else endif is called a block of code. Where If is the starting point of the block and Endif is the end point of if block. Block of code is often referred to as a group of statements.

 

Variations of if

Case 1 of If the variation

Instead of a Boolean expression, we can use mathematical expression too.

If(3-2)=1 then 
Statements 
End if
Case 2 If the variation

If a function returns a Boolean value that can be used as if.

If isString(myvar) then 
Statements 
End if
Case 3 If the variation

We can multiple tests inside of if. They are valid as long as they are yielding Boolean value.

If( isNumeric(myvar1) and (isNumeric(myvar2) Then 
Statements 
End if
Case 4 If the variation

We can use NOT statement to invert the expression.

If(NOT (isNumeric(myvar)) Then 
Statements 
End if

Else block

We can upgrade if block by attaching an else block. Else block get executed when if block is evaluated as false.

Example

If isDigit(myvar) then 
Statements 
Else 
Statements 
End if

Else If block

The Else if block is a modified multi way switch. Else If has two variants.

  • Else If with optional else
  • Plain Else if without else.
Else if with optional else
If isDigit(myvar) Then 
Statements 
ElseIf isDate(myvar) Then 
Statements 
Else 
Statements 
End If
Else If without else
If isDigit(myvar) Then 
Statements 
ElseIf isDate(myvar) Then
Statements
End If

Nesting of If Else

we can nest if else inside another if else block. There is no rule to create nested if else as Long as the logic is correct and the code is manageable. Going too deep may raise logic issues. It may create less readability and hard maintainability.

If( accountNo.IsValid( ))
    If IsEmployee(accountNo) then
       If IsVendor(accountNo) then
          msgbox "bonus is 5%"
       else
          msgbox "not a vendor anymore"
    End If
    If IsRegular(accountNo ) then
         msgbox "bonus is 7%"
    Else
         msgbox "not a valid regular employee"
    End if
    Else
         msgbox "account no does not belong to a valid employee"
    Else
         msgbox "not a valid account no"
    End if
Another Example
If isNumeric( myvar) then
   If( myvar less than 25) then  
      Statements 
   Else if((myvar less than 40) and(myvar greater than 26)) then 
      Statements 
    End if 
Else 
statements 
End if

Select case- switch

Instead of using multiple if else statement, we can use switch statements to implement multiple paths. It can test multiple conditions at a single go. Select end select block is an upgraded version of series of if end if statements.

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