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Learn QTP Step By Step

I got different requests on writting step by step description of QTP learning.I would like to thank all of my viewers to tell me to write this.

Why??

Simple...while writting this ...i got to know so many things!!!!!...Truely....while making a post on QTP learning i went through different websites... MSDN...etc. This hopping reenforce the thinking process...

Thank you again.


Well lets start:

The first thing you need to learn is VBScript...the basics..The best place to learn VB script is ---MSDN

However I have taken the required things from it...
What is a VBScript to a Automation Test Engineer?
VBScript (Visual Basic Script) …
1. It is a scripting language scaled down version of Visual Basic
2. It runs on client side.
3. Basically a syntax based language. Most VB syntaxes run on this.
4. For our purpose we always save the file as “XYZ.vbs”


The very next topic is Variable:

1. Variable: Variables are container which holds value. Before using any variables we need to declare them.(This is a best practice.) We need use dim statement to decleare. The variable declaration is nothing but allocate some amount of memory for that variable to hold some value.
Like: dim c_ball,d_count
Again this declaration can be of three type as per scope:
1. Dim Statement
2. Public Statement
3. Private Statement
Dim can be accessible from the entire script.
Public statement variables are available to all procedures in all scripts.
Private statement variables are available only to the script in which they are declared
There is a separate term called constant.
Like:
Const variable_Name=”I am a good boy”
Now this variable_Name can be used anywhere. And its value is same. The scope is public bydefault.
VBScript in itself has a number of defined intrinsic constants like vbOK, vbCancel, vbTrue, vbFalse and so on

You can also declare a variable implicitly by simply using its name in your script. That is not generally a good practice because you could misspell the variable name in one or more places, causing unexpected results when your script is run. For that reason, the Option Explicit statement is available to require explicit declaration of all variables. The Option Explicit statement should be the first statement in your script.

Naming Restrictions Variable names follow the standard rules for naming anything in VBScript. A variable name:

1.Must begin with an alphabetic character.
2.Cannot contain an embedded period.
3.Must not exceed 255 characters.
4.Must be unique in the scope in which it is declared.

Scope and Lifetime of Variables A variable's scope is determined by where you declare it. When you declare a variable within a procedure, only code within that procedure can access or change the value of that variable. It has local scope and is a procedure-level variable. If you declare a variable outside a procedure, you make it recognizable to all the procedures in your script. This is a script-level variable, and it has script-level scope.

The lifetime of a variable depends on how long it exists. The lifetime of a script-level variable extends from the time it is declared until the time the script is finished running. At procedure level, a variable exists only as long as you are in the procedure. When the procedure exits, the variable is destroyed. Local variables are ideal as temporary storage space when a procedure is executing. You can have local variables of the same name in several different procedures because each is recognized only by the procedure in which it is declared.

Assigning Values to Variables Values are assigned to variables creating an expression as follows: the variable is on the left side of the expression and the value you want to assign to the variable is on the right. For example:

B = 200

Scalar Variables and Array Variables
Much of the time, you only want to assign a single value to a variable you have declared. A variable containing a single value is a scalar variable. Other times, it is convenient to assign more than one related value to a single variable. Then you can create a variable that can contain a series of values. This is called an array variable. Array variables and scalar variables are declared in the same way, except that the declaration of an array variable uses parentheses ( ) following the variable name. In the following example, a single-dimension array containing 11 elements is declared:

Dim A(10)

Although the number shown in the parentheses is 10, all arrays in VBScript are zero-based, so this array actually contains 11 elements. In a zero-based array, the number of array elements is always the number shown in parentheses plus one. This kind of array is called a fixed-size array.

You assign data to each of the elements of the array using an index into the array. Beginning at zero and ending at 10, data can be assigned to the elements of an array as follows:

A(0) = 256
A(1) = 324
A(2) = 100
. . .
A(10) = 55

Similarly, the data can be retrieved from any element using an index into the particular array element you want. For example:

. . .
SomeVariable = A(8)
. . .

Arrays aren't limited to a single dimension. You can have as many as 60 dimensions, although most people can't comprehend more than three or four dimensions. You can declare multiple dimensions by separating an array's size numbers in the parentheses with commas. In the following example, the MyTable variable is a two-dimensional array consisting of 6 rows and 11 columns:

dim MyTable(5, 10)

In a two-dimensional array, the first number is always the number of rows; the second number is the number of columns.

You can also declare an array whose size changes during the time your script is running. This is called a dynamic array. The array is initially declared within a procedure using either the Dim statement or using the ReDim statement. However, for a dynamic array, no size or number of dimensions is placed inside the parentheses. For example:

Dim MyArray()
ReDim AnotherArray()

To use a dynamic array, you must subsequently use ReDim to determine the number of dimensions and the size of each dimension. In the following example, ReDim sets the initial size of the dynamic array to 25. A subsequent ReDim statement resizes the array to 30, but uses the Preserve keyword to preserve the contents of the array as the resizing takes place.


ReDim MyArray(25)
. . .
ReDim Preserve MyArray(30)

There is no limit to the number of times you can resize a dynamic array, although if you make an array smaller, you lose the data in the eliminated elements.
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