Computer Fundamentals Index

Computer Introduction Types of computer Characteristics of computer Uses of computer History of Computers

Computer Languages

Low Level language Middle level Language High level language

Computer Generation

Generation of Computers First Generation of Computer Second generation of Computers Third generation of Computers Fourth generation of Computers Fifth generation of Computers Sixth Generation of Computer

Peripheral Devices

Input devices Output device


Block diagram and basic components Control processing unit (CPU) Software Hardware


Computer Memory Registers Memory Hierarchy RAM Vs ROM Understanding file sizes (Bytes, KB, MB, GB, TB, PB, EB, ZB, YB)

Computer Network

Types of Network Types of Area Networks (LAN, WAN, MAN) TCP Flags

Computer Virus

Computer Virus

Computer Ports

Computer Ports


How to hack a computer How much do Computer Programmers make How does a Computer work How to associate a file with a program How does a computer convert text into binary How does a computer process data into information How to fix a CD-ROM DVD How to fix the no input signal How to install computer memory How to associate a file with a program How to log out of your operating system How do I change my name on Google How to installation or uninstallation Microsoft Paint How to fix a not a valid Win32 application error How to fix missing Microsoft Windows .dll files How to use a computer keyboard How to erase my hard drive and start over How can I test how many words I can write a minute How to shut down a computer How do I open and edit the Windows registry How to edit the registry from the command line How to restart Microsoft Windows How to install a computer processor How to open Microsoft Paint How to fix problems in Windows after installing new software How to enable or disable the preview pane of Microsoft Outlook How to open a Microsoft .wps or Works file in Word How to view the HTML source code in Microsoft Word How to View or Change the Screen Resolution of a Monitor How to Connect and Install a Computer Keyboard How to Delete Temporary Files in Windows 10 How to determine Which Version of Microsoft Office I'm using How to find out how much hard drive space is available How to Fix PC Stuck on Verifying DMI Pool Data How to choose which items show in the notification area How to find similar images using Search by Image How to fix Low Memory and out of memory errors How To Replace the CMOS Battery How do I Update my Antivirus Program How to fix a general protection fault How to Identify problems in the Windows Device Manager How can the Base be Shown How to test if a Website or Web Page is down How Much is 1 Byte, Kilobyte, Megabyte, Gigabyte, etc How to fix a CMOS checksum error How to Fix a Windows CD-ROM, DVD, or Disc Drive Issue How to Open Safe Mode How to Password Protect Files and Folders in Windows How to Reset CMOS or BIOS Settings How to use Computer Keyboard How to create a text file How to enable or disable DHCP in Windows How to test computer memory to determine if its bad How do double space or change line spacing in Microsoft Word How do I know if I have Windows Administrator Rights How many cores does my computer have How to Create a Directory or Folder How to Enter and Exit the BIOS or CMOS Setup How to change Windows Compatibility mode How to clear your internet browser history How to Connect Computer Speakers How to Copy a Web Page Link or URL How to install a Hard Drive or SSD How to Open the Windows Control Panel How to split a screen in Windows How to copy text from a scanned PDF


Who invented Computer What are the advantages of the Internet? What are the disadvantages of the Internet? Is my computer 64 bit? What is Edge Computing? What is a Router? What is Monitor What is Printer What is a Web Browser What is Microphone What is a Webcam What is PC What is Keyboard What is Motherboard What is WAP What is URL What is a Digital Assistant When was the first Computer Invented What is Modem What is Firmware What is Imperative Programming What is Protocol What is Safe Mode What is Device Driver What is Hybrid Topology What is Mesh Topology What is Procedural language What is a hyperlink What is a Username Who invented the Internet What is Video Card What is Sound Card What is Binary What does Alt+B do What does Alt+D do What does Alt+E do What does Alt+Esc do What does Alt+R do What does ALT + Q do What does Alt + Tab do What is Data Manipulation What is a touch screen What is Back Panel What is Analog Monitor What is AR lens What is an ATX Style Connector What is a File System What is Hard Disk Drive (HDD) What is a boot device What is accessibility What is Line In What is network Interface card (NIC) What is Optical Disk Where can I ask questions on the internet What is Auto Rotate What is CAD (Computer-aided design) What is Cable Modem What is Home Page What is boot menu What is braille reader What is flash memory What is Windows What is Clipboard What is Cyber Warfare What is Myspace Why has my IP address changed What is Jacquard Loom My computer is running slow, what steps can I do to fix it What is a Kensington Lock What is a multicore processor What is automation Are smartphones and tablets computers What is a Login Script What is a Loosely Typed Language What is Multitasking? Why my computer monitor shows no display or black screen What is REM What is Parallelization What is Overtype mode What is open with What is Bracket What is an Online Service What is REM What is Parallelization What is Overtype mode What is open with What is Bracket What is an Online Service What is the Pg Dn Key (Page Down Key) What is the Pg up Key (Page up Key) What is Palmtop Computer What is a Processing Device What is a Print Preview What is the Print Screen Key What can I do if my computer or laptop is lost or stolen What is a Model Number What are the currently available antivirus programs What are Toggle keys What is a Case fan What is a Silicon Chip What is a Slate PC What is a TAB stop What is an Octothorpe What is Task Pane What is Task View What is the svchost.exe file used for in Windows Where can I find free online virus scanners Why am I unable to increase the resolution in Windows What is Autofill When I click my mouse, it sometimes double-clicks What is Scratch What is UDIMM What is MsConfig What is an Expansion Card What is an Executable File What is an Elevated Command Prompt What is an AC Adapter What is AIMBOT What is a Software Suite What is a LED Monitor What does Alt + X do What does alt + space do What does Alt + O do Now that I’ve got a Computer, what can i do What is a Punch Card What is RDIMM What is Select All What is Serial number What is Thermos flask What programs can I use for speech recognition What are the Advantages of Computers What are the Disadvantages of Computers What does Alt + T do What Hardware Device Drivers should be Updated What is a Desktop What is a Ring Topology What is CMOS What is a Directory What is a Mechanical Mouse What is a Plotter What is a Variable What is an Icon What is Data What is HDMI What is Remote What is Right-Click What is SMPS Why does my Laptop not turn on What is a Copyright What is a Cordless Mouse What is a CSV file What is a Joystick What is a Start Button What is a Taskbar What is an Alignment What is an Output Device What is Cat 5 What is Google Chrome What is Post What are Recordable DVD Drives What Does Alt + F4 Do What Does Alt + L Do What is a bit (Binary Digit) What is a cable What is a Calculator What is a capacitor What is a Cold Boot What is a Dialog Box What is a Dual-boot What is a Slide What is A4 What is AM What is Barcode Reader What is EHCI What is a Header What is a Joystick What is a Secondary Storage Device What is Access Time What is Account Sharing What is an Asterisk What is Asynchronous DRAM What is Back Quote What is BIOS What is Borderless Printing What is Case Badge What is CD-ROM What is Chat Slang What is Composite What is RJ Cable What Are Bottom Row Keys What is SAN What is Tray What is VDU What Does Alt + M Do What Does Alt + P Do What is a Cell What is a Command Key What is a key Combination What is a Menu Bar What is a Startup What is a T What is Chat What are the F1 through F12 keys What does Alt + Enter do What Does Alt + Home DO What does Alt + R do What does Ctrl + B do What Does Ctrl + Enter Do What Does Ctrl + R Do What does Ctrl + G do What does Ctrl + 9 do What does Ctrl + End do What does Ctrl + O do What Does Ctrl + P do What Does Ctrl + Q do What is a Colon What is a Core What is Apple Touch Icon What is Clock What is Code What is Computer Crime What is Ctrl What is DAT What is Data diddling What is Date Why won't my computer turn on What Does Alt + N Do What does ctrl + 2 do What does ctrl + space do What does Ctrl + W do What does Ctrl + T Do What Does Ctrl + 2 do What does Ctrl + 5 Do What are the most common file types and file extensions What are Sticky keys What Does Ctrl + Shift + Esc Do What is Settings What is Task Manager What is Taskbar What is a DNS Resolver What does ctrl + 1 do What does ctrl + 0 do How to install software What is a Folder What is a Legend What is a MAC Address What is a Path What is a Ruler What is a Toolbar What is an Intranet Meaning and Differences with Internet What is an SSD What is Inheritance What is Tablet What is Depth What is Docking Station What is Double Click What is a Solid Ink Printer What is a Temporary File What is Backup and Restore What is Electronic Payment Systems Eps What is Marshalling


Difference between hardware and software Difference between multiprocessor and distributed systems Difference between Desktop and Laptop Difference between File and folder Difference between Hard Copy and Soft Copy Open Source Programs vs Closed Source Programs Difference between Optical Fibre and Coaxial Cable Difference between Website and Webpage Difference between Classes and Objects Input VS Output Difference between Primary and Secondary Storage with Examples


Quantum Computing Computer Software Autoexec.bat and config.sys info Update an Antivirus Use of Internet Advantages and disadvantages of Email Computing Power Internet Explorer Shortcut Keys Advanced Encryption Standard (AES) Augmented Reality Infrastructure Readiness Check Top 10 Internet tips and tricks Introduction and Features of FoxPro Features of Multimedia Top 10 online services and applications Receiving S.M.A.R.T. status bad backup and replacing error Version Control System Uninstalling Software or Apps in Windows Data Warehouse Increase or decrease font size in Word using keyboard shortcuts Mouse not detected or working in Windows Computer Cleaning Information and Steps Function Keys on Keyboard Windows 7 Alt+Tab won’t stay on top or stick 10 Essential Examples of Web Browsers Binary Subtraction using 2’s Complement Case Sensitive Languages Computer Pioneers and people who are CEO Microsoft Word Shortcut Keys Parts of Computers Names, Definitions and Images ROM and its Types Basics of Information Technology Characteristics of a Good Software Design Characteristics of Management Information System Classification of Management Information System Implementation of MIS Input Devices of Computer Definition Limitations of Management Information System 3 Types Of Network in Computer Block Diagram Of Control Unit Difference Between Computer and Embedded System Difference Between Hard Disk and Floppy Disk Abstraction in OOAD Hardware and Software Devices Optomechanical Mouse CMOS Memory What is a Terminal? What is Graphic Design? What is Load? What is Passcode? What is Reboot? What is Registry? What is Safe Mode? What is Standby? What is SYN (Synchronize)? What is Task Manager? Attribute Computing BPS in Computer Bulletin Board System Light Pen Input Device 3 TYPES OF NETWORK IN COMPUTER Block diagram of control unit What is a Solid Ink Printer? What is a Temporary File? What is an App launcher? What is Backup and Restore? What is a Tab Character? What is the Core i3? What is Paint? What is a Workbook? Advantages and Disadvantages of Online Education What is a String? What is a VDU (Visible Display Unit)? 50 Uses of Computer What is Workspace? What is a Procedural Language? What is VGA (Video Graphics Array)? Object Linking and Embedding in MS Word Semiconductor Memory Types of Parallel Computing Web Resources Difference between Virus, Worm and Trojan Horse Difference between HQ (High Quality) and HD (High Definition) What is Text Wrapping What is Timestamp? Semiconductor Ram Memory What is a File Attribute? What is a Video Call? Difference between SDRAM and DDR What is ANSI? Difference between DOS and Windows How to Set the Path and Environment Variables in Windows? Mainframe System What is ScanDisk? C drive in Mac Computer Memory Table How to Change the Keyboard Language in Windows? What is a Video Call? What is a Zoom Slider? What is Floppy Disk in Computer What is the most Popular Operating System? OMR in Computer What is a Work Area?

Difference between Classes and Objects

What is Class?

A class in C++ is a blueprint for creating objects (data structures), providing initial values for state (member variables or attributes), and implementations of behavior (member functions or methods).

A class definition begins with the word "class," then lists the class's name and body inside curly braces.The class body is where the member variables and member functions can be declared.


class ClassName {
    // member variables (also called data members or attributes)
data_type member_variable_1;
data_type member_variable_2;
    // member functions (also called methods)
return_type member_function_1(parameters) {
        // function body
return_type member_function_2(parameters) {
        // function body


ClassName is the name of the class. The accessibility of the members of the class is determined by the access specifier public. Private members can only be accessed within the class, but public members can be accessed from anywhere in the application.

Data's type, or data type, can be an int, float, string, etc.member_variable_1, member_variable_2, etc. are the names of the member variables.The type of the value returned by the member function, such as int, void, etc., is known as return type.member_function_1, member_function_2, etc. are the names of the member functions. Parenthesis and commas separate the input parameters for the member function, which are denoted by parameters. If a member function does not take any input parameters, then the parentheses are left empty.The function body is enclosed in curly braces and contains the code that implements the behavior of the member function.


#include <bits/stdc++.h>
using namespace std;
class Rectangle
int width, height;
voidset_values(int x, int y);
void area()
int ar = width * height;
cout<<"Area is: "<<ar<<endl;
void Rectangle::set_values(int x, int y)
width = x;
height = y;
int main()
  Rectangle z;
z.set_values(10, 20);


Area is: 200


In this example, the class Rectangle has two member variables width and height, and two member functions set_values and area. The set_values function sets the values of width and height, while the area function calculates and returns the area of the rectangle.

Access specifieer:

In object-oriented programming (OOP), access specifiers are keywords that specify the visibility and accessibility of class members like fields, methods, and constructors. These keywords control which parts of a class can be accessed by other objects, classes, and even outside of the program. There are three main access specifiers in OOP: public, private, and protected.

  • Public: Anywhere in the program, whether in the same class, a subclass, or from a completely other class, can access members that have been designated as public.The main purpose of public access specifiers is to make members available to the rest of the program.
  • Private: Only other members of the same class may access members that have been designated private.They are hidden from all other classes and objects and cannot be accessed directly from outside the class. This is useful for hiding implementation details that are not relevant to other parts of the program.
  • Protected: Within the same class and its subclasses, members that have been designated as protected can be accessed. This allows the members to be accessed by subclasses, but not by other classes or objects outside of the class hierarchy. This is useful for creating a base class that can be extended by other classes while still maintaining control over the accessibility of its members.

In conclusion, access specifiers are an important aspect of OOP as they provide a means of controlling access to class members and maintaining the encapsulation and abstraction of a class. Public, private, and protected access specifiers each have their own use cases and provide different levels of visibility and accessibility for class members.


#include <iostream>
class Base {
int public_field;
int private_field;
int protected_field;
class Derived : public Base {
voidaccess_fields() {
public_field = 1;
protected_field = 2;
    // private_field = 3; // error: private_field is private
int main() {
  Base base;
base.public_field = 1;
  // base.private_field = 2; // error: private_field is private
  // base.protected_field = 3; // error: protected_field is protected
  Derived derived;
derived.public_field = 10;
  // derived.private_field = 20; // error: private_field is private
std::cout<< "Base public_field: " <<base.public_field<<std::endl;
  // std::cout<< "Base private_field: " <<base.private_field<<std::endl; // error: private_field is private
  // std::cout<< "Base protected_field: " <<base.protected_field<<std::endl; // error: protected_field is protected
std::cout<< "Derived public_field: " <<derived.public_field<<std::endl;
  // std::cout<< "Derived private_field: " <<derived.private_field<<std::endl; // error: private_field is private
  // std::cout<< "Derived protected_field: " <<derived.protected_field<<std::endl; // error: protected_field is protected
return 0;


Base public_field: 1
Derived public_field: 1


The program demonstrates the use of the access specifiers public, private, and protected in C++. The class Base defines three fields: public_field, private_field, and protected_field. Since the field public field is marked as public, anyone outside of the class can access it. Since the field private field is marked as private, only members of the class may access it. Since the field protected field is marked as protected, only members of the class and its subclasses can access it.

The class Derived is a subclass of Base and is declared as public. This means that it can access the public_field and protected_field of the Base class. In the method access_fields(), the public_field and protected_field can be accessed, but the private_field cannot be accessed as it is private.

In the main function, an instance of Base is created and the value of its public_field can be assigned and printed to the screen. However, the values of the private_field and protected_field cannot be assigned or printed to the screen as they are private and protected, respectively.

An instance of Derived is also created and its public_field can be assigned a value and printed on the screen. The access_fields() method is called on the Derived object, which sets the values of the public_field and protected_field. The values of the public_field and protected_field are then printed on the screen, demonstrating that they can be accessed from the Derived class.

What is an Object?

C++ is an object-oriented programming language that provides the features to create objects, encapsulate data and methods, and implement inheritance and polymorphism. In C++, an object is an instance of a class, which serves as a template for building objects. A class defines the properties and behaviors of objects of its type.

Objects are fundamental to object-oriented programming (OOP), which is a programming paradigm that focuses on the manipulation of objects rather than the management of code and data. Objects encapsulate data and behavior into a single entity, making it easier to understand and work with complex systems.

In C++, objects are created from classes. A class describes the traits and actions of an object's type and serves as a template for building new objects.Each object created from a class is unique, with its values for its member variables.

Objects can communicate with each other by sending messages to each other. In C++, this is done by calling the member functions of objects. A member function is a unique kind of function that is connected to a class and can be used with one of the class's objects.

Objects can also be used to model relationships between entities. For example, you can define a Student class and a Teacher class, and you can create objects of both classes to represent real-world students and teachers. The Student class could have a member function that returns the name of the teacher, and the Teacher class could have a member function that returns the names of the students in a class.

Inheritance is another key feature of objects in C++. You can build a new class from an existing class using inheritance.You can add more properties and behaviors to the new class as needed; it will inherit all of the previous class's attributes and behaviors. This allows you to create more specialized classes that are based on more general classes.

Polymorphism is another important feature of objects in C++. Different types of objects can be viewed as belonging to the same type thanks to polymorphism. This enables you to write code that is more flexible and reusable, as it can work with objects of different types in the same way.

In conclusion, objects are a crucial component of OOP and a strong tool for organizing and organizing your code.They encapsulate data and behavior, and they allow you to model real-world entities and relationships in your programs. With features like inheritance and polymorphism, objects provide a rich and flexible mechanism for writing high-quality, maintainable, and reusable code.


#include <iostream>
#include <string>
using namespace std;
class Person {
string name;
int age;
void display() {
cout<< "Name: " << name <<endl;
cout<< "Age: " << age <<endl;
int main() {
  Person person1; = "John Doe";
  person1.age = 30;
return 0;


Name: Joe Doe
Age: 30


In this example, a class named Person is defined, with name and age as its member variables and a display() member function. In the main function, an object named person1 is created from the Person class and its member variables are assigned values. The display() member function is called on the person1 object, which displays its properties.

This simple example only serves to show how to create an object in C++.In real-world programs, classes are usually more complex and have more member variables and member functions. Additionally, objects are often created dynamically, using the new operator, or they can be passed as arguments to functions or returned from functions.

Difference between Class and Objects


  • Provide a blueprint or template for creating objects
  • Define the attributes (data) and behaviors (methods) of objects
  • Do not contain actual data, but describe what the data of objects will look like
  • Are created at design time and exist in memory only as long as the program is running
  • Can be reused to create multiple objects


  • Represent a specific instance of a class
  • Contain actual data, which is unique to each object
  • Are created at runtime and exist in memory until they are destroyed or the program terminates
  • Follow the blueprint defined by the class to have specific attributes and behaviors
  • Can interact with other objects and respond to messages or events

The use of classes in object-oriented programming (OOP) allows for the formal modeling of real-world notions. By defining the attributes and behaviors of objects, classes provide a blueprint for creating objects that have a consistent structure and behavior. This helps to reduce the complexity of the code and makes it easier to manage and maintain the code over time.

On the other hand, objects are runtime-generated instances of a class. Objects contain the data that is specific to that instance of the class, and they exhibit the behaviors that are defined in the class. When a program is running, multiple objects can be created from the same class, each with its unique data.

For example, consider a class called "Person". The Person class might have attributes such as name, age, and address. The Person class might also have behaviors such as introducing, speaking, and listening. Each instance of the Person class, or each Person object, would have its specific values for name, age, and address, but would exhibit the same introduce, speak, and listen to behaviors as every other Person object.

In conclusion, the relationship between classes and objects is an important aspect of OOP. Classes provide a blueprint for creating objects, while objects are instances of classes that contain specific data. The code is made simpler by this structure, which also makes it simpler to manage and maintain over time.