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?

What is a Variable?

In our daily life, the variable plays an important role in programming as well as in mathematics for storing data or information. Most mathematicians tend to assume variables for solving problems. In programming languages like C, JAVA, C++, etc., the variable has different definitions, but the use and application are the same.

For Example, let’s assume that the variable is kind of like a square box shown below with a label. In this case, the label is X; this is a special square box that holds a single number within it. We can't see what number is inside the square bucket. We will need a clue to figure out what that number is. Here is an example of what a clue might look like.

What is a Variable

This above clue is called an equation because of the equal sign. The square tends to save the value 2 in the box. This is the role of a variable and also the best example to understand.

Now we are going to discuss the variables in different programming languages.

In research, we also use a variable, which is referred to as it is a logical set that has some attributes. In research, attributes are closely related to that variables, and in the programming aspect, also we relate attributes to a variable.

Variable in C Language

The name of the memory location is known as a variable where the data is stored. We can alter the value of a variable. In C, we have the address of the variable, and an address is different from the value. A variable is a symbolic representation in terms of programming language.


int main(){
int a;
int b;
printf(“the value of a=%d”, a);
printf(“the value of b=%d”,b);
return 0;


the value of a=4
the value of b=8 

The above example can explain how a variable works and how we store the value in the variable.

There are different types of variables as below:

1. Local Variable

2. Global Variable

3. Static Variable

4. Automatic Variable

5. External Variable

Local Variable: Variable that is declared or initialized inside the functions are called Local Variable.


void main(){
int a=3; #this is the local variable initialized after declaring the variable

Global Variable: The variables declared outside the functions are called Global Variables.


int a=5; #this is the variable declared outside the main function
int areaS(){
int area;
return area;
void main(){
printf(“the area of the Square: %d”,areaS());


The area of the Square: 25 

Static Variable: Variables declared with a keyword static are static variables whose lifetime is throughout the program run time.


Void sum(){
Int a=3;
Static int b = 4;
printf(“the value of a=%d and b=%d”, a, b);


The value of a=5 and b = 6

Automatic Variable: Variables declared with auto keywords are known as automatic variables.


void main(){
int a = 3;
auto int b = 4;
printf(“a=%d, b=%d”,a,b);


a=3, b=4

External Variable: Eternal variables are used to share the variables among the multiple C files.


Program1: save.h

Extern int x=1, y=3;

Program 2: intro.c

Void main(){
Int sum;
Printf(“x=%d\n”, x);
printf(“sum=%d”, sum);



The explanation for the above program:

You need to save the file as save.h in a separate folder and write the code as given. Create another file as intro.c, which is a c file, and write #include<save.h>, which will import the external file.

Each object in object-oriented programming includes the data variables of the class of which it is an instance. The methods of the object are made to deal with the actual values that are presented to it when it is utilized.

Rules that should be followed while naming a variable in C:

  • Only letters (including uppercase and lowercase characters), numbers, and underscore are permitted in variable names.
  • A variable's first letter must either be a letter or an underscore.
  • There is no restriction on the length of a variable name or identifier. However, if the variable name is larger than 31 characters, you can have issues with some compilers.                 

This is all about variables in C language, where we came to know the different types of variables and their programs. We have the explanation for the codes and the rules for writing the variables.

Variable in JAVA

In JAVA, we need to define the variable in a different manner, and A variable is a container that is used to store the data values in it. It is a case-sensitive language. In Java, there are three two types of datatypes for initializing the variables that are listed below:

  • Primitive
  • Non-Primitive

In Java, there are different types of datatypes to initialize the variable that are:

  1. int
  2. string
  3. float
  4. char
  5. boolean

Compared to C language, it has two different datatypes, that are string and Boolean, and string is used to initialize a text or group of characters, whereas Boolean has two statements, True and False.

In Java, we also have a final variable that can be initialized, and we cannot change the value.

In Java, the variable has three classifications that are listed below:

  1. Local variable
  2. Static variable
  3. Instance variable

Local Variable:

Local variables are variables that are declared inside the method body. Only that method may utilize this variable, and the other methods in the class are completely unaware of its existence.

Static Variable:

Static variables are those that have been explicitly designated as static. It can't be regional. The static variable can be created once and shared across all of the class instances. When the class is loaded into memory, static variable memory is only allocated once.

Instance Variable:

An instance variable is a variable that is declared inside a class but outside the method's body. It has not been designated as static. Because its value is instance-specific and not shared across instances, it is known as an instance variable.

For example:

public class A
static int a=20; 
void method()
int b = 30;
Public static void main(String arg[])
int c=40;

The explanation for the above program:

In the above program, we can see static int a = 20, which is declared, and that is a static variable that is not local. int b = 30 comes under the local variable, which can be utilized only under the void method() function. int c = 40 is a variable that is initialized outside of the method body.

In Java, if we have a memory, we need to create space for creating a variable where it utilizes that space. The area which we have created to store the value can be altered or can be changed.

Variable in C++

A simple variable definition consists of a type specifier followed by a list of one or more variable names separated by commas and ends with a semi-colon.

C++ language is the same as that C language in that we have the same classifications as that C language. In this, the keywords changes from C.

For example:

using namespace std;
int main(){
int a=30;
cout << a;
return 0;



Variable in Python

There is no requirement to create variables in advance while using Python, nor does it want you to define the data type at the time of variable creation.

There are 4 major datatypes that are used to initialize the variable:

  1. Numbers
  2. String
  3. List
  4. Tuple

Rules for defining a variable in Python:

  • The underscore character or a letter must come first in a variable name.
  • No number may begin a variable name.
  • Only underscores (A-z, 0-9, and _) and alphanumeric characters are permitted in variable names.
  • Names of variables are case-sensitive (alphabet, Alphabet, and ALPHABET are three different variables)

For example:

b=”Hello, world!”


Hello, world!