# CBSE Class 12 Informatics Practices Procedures Functions And Modules Notes

Download CBSE Class 12 Informatics Practices Procedures Functions And Modules Notes in PDF format. All Revision notes for Class 12 Informatics Practices have been designed as per the latest syllabus and updated chapters given in your textbook for Informatics Practices in Standard 12. Our teachers have designed these concept notes for the benefit of Grade 12 students. You should use these chapter wise notes for revision on daily basis. These study notes can also be used for learning each chapter and its important and difficult topics or revision just before your exams to help you get better scores in upcoming examinations, You can also use Printable notes for Class 12 Informatics Practices for faster revision of difficult topics and get higher rank. After reading these notes also refer to MCQ questions for Class 12 Informatics Practices given our website

## Procedures Functions And Modules Class 12 Informatics Practices Revision Notes

Class 12 Informatics Practices students should refer to the following concepts and notes for Procedures Functions And Modules in standard 12. These exam notes for Grade 12 Informatics Practices will be very useful for upcoming class tests and examinations and help you to score good marks

### Procedures Functions And Modules Notes Class 12 Informatics Practices

Procedures, Functions and Modules

It’s a named unit of a group of program statement that performs a well defined task. This unit can be called from the calling program.

Role of Procedure:

Increase Reusability – Using same code again and again.

Modularization – Means to divide a Big program into small modules.

1) Sub -           A procedure performs a task and does not return a value.

Private/Public Sub Procedure-Name( parameter list) Statements End Sub

Eg: Write a VB Procedure that receives a number and check that it is even or odd.

Called Procedure:-

Sub checkEvenOdd (x as Integer)

If x mod 2 = 0 then

Print “Even No.”

Else

Print “Odd No.”

End if

End Sub

Calling Program:-

Private sub command1_click( )

Dim A as Integer

A = val(Inputbox(“Enter a No”))

Call checkEvenOdd (A)

End Sub

2) Function - A procedure performs a task and returns a value.

Private/Public Function Function-Name( parameter list)

Statements

End Function

Eg: Write a VB Function that receives a number and Returns True if it is even otherwise False.

Called Function:

Function checkEvenOdd (x as Integer) As Boolean

If x mod 2 = 0 then

checkEvenOdd = TRUE

Else

checkEvenOdd = FALSE

End if

Calling Program:

Private sub command1_click( )

Dim x as Boolean

Dim A as Integer

A = val (Inputbox (“Enter a No”) )

x = checkEvenOdd (A)

If x = TRUE then

Msgbox “Even No.”

Else

Msgbox “Odd No.”

End If

End Sub

Call byVal and Call byRef:-

The call byVal method copies the values of actual parameter into the formal parameters, ie. The procedure creates its own copy of argument values and then uses them. Only a copy of a variable is passed to the called procedure and if the procedure changes the value, the changes affects only the copy and not reflected back to the original variable itself.

Sub DemoByValue( ByVal x as Intyege )

x = x + 10

Print x

End Sub

Private sub mainprg( )

Dim A as Integer

A = 10

Print A

Call DemoByValue( A)

Print A

End Sub

The O/P is:

10

20

10

The call byRef method does not creates its own copy of original values, rather it refers to the original values only by different names called reference, and thus the called procedure works with the original data and any changes in the values gets reflected to thedata.

Sub DemoByReference ( ByRef x as Integer )

x = x + 10

Print x

End Sub

Private sub mainprg( )

Dim A as Integer

A = 10

Print A

Call DemoByReference ( A)

Print A

End Sub

The O/P is:

10

20

20

Code Modules:-

A module is a container in VB, that contain some variables, procedures and definition.

Three types of Modules are:

1) Form Module - Stores all the procedures and declarations pertaining to single form. Form modules are stored with .FRM extension.

2) Standard Module - Store general purpose code of the application, ie code and declaration that are not specific to a form. Standard modules are stored with .BAS extension.

3) Class Module - It stores the blueprint for user created custom object. Class modules are stored with .CLS extension.

Variable Scope: -

The part of a program within which a variable is accessible, is known as its scope.

Three Variable Scopes are:

1) Private Scope/ Local Scope - Variables declared within a procedure are in local scope.

2) Module Scope  - Variables available for all the procedures within that module.

3) Public Scope / Global Scope - Variables declared with public statement and available to the application.

Static Variables: Local and Static variable differ by their life span. Static variables retain its value even after the procedure has finished executing.

Which variable is static in the following function?

Static function MyFunction ( )

Static X1 as Integer

Dim Y1 as Integer

End Function

Ans: - Both X1 and Y1 are static variables because a Static function makes all its local variables Static.