# CBSE Revision Notes for class 12 Computer Science

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## Computer Science Revision Notes CBSE class 12

We think the first step is motivating yourself to revise. What are you trying to achieve here? What’s your ultimate goal? Make a schedule for your revision and be realistic about it. Figure out how much time you can spend on a task each day. The important part of exam preparation and the key to success, as the more you revise these notes. These revision notes are prepared by our finest and experienced teachers. You can download class 12 Computer Science Revision Notes in PDF format. These Revision Notes are also available in the myCBSEguide website and mobile app for free.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Term 1 - Python Revision Tour Revision of the basics of Python Functions: scope, parameter passing, mutable/immutable properties of data objects, pass arrays to functions, return values, functions using libraries: mathematical, and string functions. File handling: open and close a file, read, write, and append to a file, standard input, output, and error streams, relative and absolute paths. Using Python libraries: create and import Python libraries Recursion: simple algorithms with recursion: factorial, Fibonacci numbers; recursion on arrays: binary search Idea of efficiency: performance defined as inversely proportional to the wall clock time, count the number of operations a piece of code is performing, and measure the time taken by a program. Example: take two different programs for the same problem, and understand how the efficient one takes less time. Data visualization using Pyplot: line chart, pie chart, and bar chart. Data-structures: lists, stacks, queues.

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Download CBSE Revision Notes for CBSE Class 12 Computer Science Term 1 - Working with Functions Functions: scope, parameter passing, mutable/immutable properties of data objects, pass arrays to functions, return values, functions using libraries: mathematical, and string functions.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Python Libraries Using Python libraries: create and import Python libraries

Download CBSE Revision Notes for CBSE Class 12 Computer Science Term 1 - File Handling File handling: open and close a file, read, write, and append to a file, standard input, output, and error streams, relative and absolute paths.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Recursion Recursion: simple algorithms with recursion: factorial, Fibonacci numbers; recursion on arrays: binary search

Download CBSE Revision Notes for CBSE Class 12 Computer Science Idea of Efficiency The idea of Algorithmic Efficiency. performance defined as inversely proportional to the wall clock time, count the number of operations a piece of code is performing, and measure the time taken by a program. Example: take two different programs for the same problem, and understand how the efficient one takes less time.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Data Visualisation using Python (Deleted) Data Visualisation using Python. Data visualization using Pyplot: line chart, pie chart, and bar chart.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Term 2 - Data Structures – lists, stacks and Queues Data Structures – lists, stacks and Queues.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Term 2 - Computer Networks and Devices Structure of a network: Types of networks: local area and wide area (web and internet), new technologies such as cloud and IoT, public vs. private cloud, wired and wireless networks; concept of a client and server. Network devices such as a NIC, switch, hub, router, and access point.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Term 2 - SQL Commands SQL Commands. SQL commands: aggregation functions – having, group by, order by.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Creating a Django based Basic Web Application (Deleted) Creating a Django based Basic Web Application. Write a minimal Django based web application that parses a GET and POST request, and writes the fields to a file - flat file and CSV file.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Term 2 - Interface Python with mySQL Write a minimal Django based web application that parses a GET and POST request, and writes the fields to a file - flat file and CSV file. Interface Python with an SQL database SQL commands: aggregation functions – having, group by, order by.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Object Oriented Programming in CPP (OLD) Object Oriented Programming: Concept of Object Oriented Programming – Data hiding, Data encapsulation, Implementation of Object Oriented Programming concepts in C++: Definition of a class, Member of a class Constructor and Destructor Special Characteristics, declaration and definition of destructor Inheritance (Extending Classes Data File Handling: Need for a data file, Types of data files – Text file and Binary file basic file operations on text file Binary File Components of C++ to be used with file handling Header file: fstream.h; ifstream, ofstream, classes Introduction to Pointer, Declaration and Initialization of Pointer self referencial structure etc

Download CBSE Revision Notes for CBSE Class 12 Computer Science Data Structures (OLD) Introduction to data structure- array, stack queues primitive and non-primitive data structure, linear and non-linear structure, static and dynamic data structure. One and two Dimensional arrays: Sequential allocation and address calculation; Stack (Array and Linked implementation of Stack): Introduction to stack (LIFO_Last in First out Operations) Queue: (Array and Linked Implementation) Introduction to Queue (FIFO – First in First out operations) Operations on Queue (Insert and Delete and its Implementation in C++, circular queue using array.

Download CBSE Revision Notes for CBSE Class 12 Computer Science DBMS and SQL (OLD) Data base Concepts: Introduction to data base concepts and its need. Relational data model: Concept of domain, tuple, relation, key, primary key, alternate key, General Concepts: Advantages of using SQL, Data Definition Language and Data Manipulation Language SQL functions: SUM ( ), AVG ( ), COUNT ( ), MAX ( ) AND MIN ( ); Obtaining results (SELECT query) from 2 tables using equi-join, Cartesian product and Union Note: Implementation of the above mentioned commands could be done on any SQL supported software on one or two tables.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Boolean Algebra (OLD) Role of Logical Operations in Computing. Binary-valued Quantities, Boolean Variable, Boolean Constant and Boolean Operators: AND, OR, NOT; Truth Tables; Closure Property, Commutative Law, Associative Law, Identity law, Inverse Law, Principle of Duality, Idempotent Law, Distributive Law, Absorption Law, Involution Law, DeMorgan's Law and their applications; Obtaining Sum of Product (SOP) and Product of Sum (POS) form the Truth Table, Reducing Boolean Expression (SOP and POS) to its minimal form, Use of Karnaugh Map for minimization of Boolean expressions (up to 4 variables); Application of Boolean Logic: Digital electronic circuit design using basic Logic Gates (NOT, AND, OR, NAND, NOR) Use of Boolean operators (NOT, AND, OR) in SQL SELECT statements Use of Boolean operators (AND, OR) in search engine queries.

Download CBSE Revision Notes for CBSE Class 12 Computer Science Communication Technologies (OLD) Evolution of Networking: ARPANET, Internet, Interspace Data Communication terminologies Transmission mediaNetwork devices Network Topologies and types Network ProtocolMobile Telecommunication Technologies Protocols for Chat and Video Conferencing VOIP Network Security Concepts India IT Act, Cyber Law, Cyber Crimes, IPR issues, hacking.Introduction To Web services Domain Names E-commerce payment transactions using online banking, mobile banking and payment apps and services.

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# CBSE Class12 Notes and Key Points

• CBSE Revision notes for Class 12 Computer Science PDF
• CBSE Revision notes Class 12 Computer Science – CBSE
• CBSE Revisions notes and Key Points Class 12 Computer Science
• Summary of the NCERT books all chapters in Computer Science class 12
• Short notes for CBSE class 12th Computer Science
• Key notes and chapter summary of Computer Science class 12
• Quick revision notes for CBSE board exam

## CBSE Class 12 Computer Science Chapter-wise Revision Notes

• Chapter 1 – Review of Python
• Chapter 2 – Concept of Object Oriented Programming
• Chapter 3 – Classes in Python
• Chapter 4 – Inheritance
• Chapter 5 – Linear List Manipulation
• Chapter 6 – Stacks & Queues in list
• Chapter 7 – Data File Handling
• Chapter 8 – Exception Handling & Green Functions
• Chapter 9 – Databases Concepts and SQL
• Chapter 10 – Structure  Query Language
• Chapter 11 – Boolean Algebra
• Chapter 12 – Boolean Functions & Reduce Forms
• Chapter 13 – Application of Boolean Logic
• Chapter 14–  Networking Concepts  (Part 1)
• Chapter 15 – Networking Concepts  (Part 2)
• Chapter 16 – Networking Protocols
• Chapter 17 – Mobile Telecommunication Technologies, Network Security and Internet Services

Key Notes for CBSE Board Students for Class 12. Important topics of all subjects are given in these CBSE notes. These notes will provide you overview of the chapter and important points to remember. These are very useful summary notes with neatly explained examples for best revision of the book.

## CBSE Class-12 Revision Notes and Key Points

CBSE quick revision note for class-12 Computer Science, Chemistry, Maths, Biology and other subject are very helpful to revise the whole syllabus during exam days. The revision notes covers all important formulas and concepts given in the chapter. Even if you wish to have an overview of a chapter, quick revision notes are here to do if for you. These notes will certainly save your time during stressful exam days.

CBSE Class 12 Computer Science 1
Revision Notes (Review of Python)

Interactive Mode: Interactive Mode, as the name suggests, allows us to interact with OS.

Script Mode: In script mode, we type Python program in a file and then use interpreter to execute the content of the file.

Number: Number data type stores Numerical Values.

Sequence: A sequence is an ordered collection of items, indexed by positive integers.

Arithmetic operators: +, -, *, /, %, ** and //.

Relational operators: <, <=, >, >=, != or <> and ==.

Logical operators: or, and, and not

Assignment Operator: =, +=, -=, *=, /=, %=, **= and //=

Functions in Python: A function is named sequence of statement(s) that performs a computation.

Module: A module is a file containing Python definitions (i.e. functions) and statements. Standard library

of Python is extended as module(s) to a Programmer.

String: In python, consecutive sequence of characters is known as a string. An individual character in a string is accessed using a subscript (index).

List: Like a string, list is a sequence of values. List can be of any type.

Dictionaries: A dictionary is like a list, but more in general. In a list, index value is an integer, while in a dictionary index value can be any other data type and are called keys.

Tuples: A tuple is a sequence of values, which can be of any type and they are indexed by integer.

(Concept of Object Oriented Programming)

Object: clearly defines an entity in terms of its properties and behaviour.

Class: a blueprint of an object.

Encapsulation: combining of data and the functions associated with that data in a single unit

Data Hiding: the mechanism of hiding the data of a class from the outside world

Abstraction: providing only essential information to the outside world and hiding their background details

Inheritance: forming a new class (derived class) from an existing class (called the base class).

Polymorphism: ability to use an operator or function in various forms.

Static Binding: the linking of function call to the function definition is done during compilation of the program.

Dynamic Binding: the linking of function call to the function definition is done during the execution of the program.

(Classes in Python)

Namespace: A mapping from names to objects. Examples of namespaces are built-in names, global names in a module and local names in function invocation

Scope: A region of Python program where a namespace is directly accessible.

In Python a name, storing any type of data, can refer to only one thing at a time.

The scope of a variable is its enclosing function, class or file.

The names always belong to the namespace where they are bound.

Names declared with global keyword have to be referred at the file level.

LEGB rule: when a name is encountered during the execution of the program, it searches for that name in the following order:

L. Local - It first makes a local search i.e. in current def statement.

E. Enclosing functions - It searches in all enclosing functions, form inner to outer.

G. Global (module) - It searches for global modules or for names declared global

B. Built-in (Python) - Finally it checks for any built in functions in Python.

Class definitions should be given before it is referenced.

__init__ is a special method used to initialize the members of a class.

self is the first argument that is passed to the methods of a class.

A class object can be used in two ways - Instantiation and Attribute reference Class attributes belong to the class and will be shared by all instances Instance attributes belong to a particular instance of a class only.

The attributes - data and methods can be added to the class dynamically.

getattr(obj, name,[ default]): is used to access the attribute of the object

hasattr(obj,name): is used to check if an attribute exists or not

setattr(obj,name,value): is used to set an attribute with a value.

delattr(obj,name) : is used to delete an attribute

__dict__ : gives the dictionary containing class namespace

__doc__: returns the docstring of a class

__name__: it gives the class name

__module__: specifies the module name in which the class is defined

__bases__: it gives a tuple containing base classes

__del__: is invoked when the module is being deleted

__str__: returns the string representation of the objects Private variables can only be accessed from inside the objects.

Name Mangling: A name is prefixed with two leading underscores and no more than one trailing underscore.

Static Method: is a method that does not obey the usual convention in which self, an instance of the class, is the first argument to the method.

Python uses  two  strategies  for  memory  allocation-  Reference  counting  and  Automatic  garbage collection.

Reference Counting: works by counting the number of times an object is referenced by other objects in the system. When an object's reference count reaches zero, Python collects it automatically.

Automatic Garbage Collection: Python schedules garbage collection based upon a threshold of object allocations and object  de-allocations.  Whe  the  number  of  allocations  minus  the  number  of  deallocations are greater than the threshold number, the garbage collector is run and the unused block of memory is reclaimed.

(Inheritance)

Inheritance: In object oriented programming, inheritance is a mechanism in which a new class is derived from an already defined class. The derived class is known as a subclass or a child class. The pre-existing class is known as base class or a parent class or a super class.

Single Inheritance: In single inheritance a subclass is derived from a single base class.

Multilevel Inheritance: In multilevel inheritance, the derived class becomes the base of another class.

Multiple Inheritance: In this type of inheritance, the derived class inherits from one or more base classes.

Hierarchical Inheritance: In this type of inheritance, the base class is inherited by more than one class.

Hybrid Inheritance: This inheritance is a combination of multiple, hierarchical and multilevel inheritance.

Overriding Methods: The feature of overriding methods enables the programmer to provide specific implementation to a method in the subclass which is already implemented in the superclass.

Abstract Methods: An abstract method is a method declared in a parent class, but not implemented in it. The implementation of such a method can be given in the derived class.

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