Scope of a variable

The scope of a variable in programming refers to the region of the program where the variable can be accessed or modified. It defines the visibility and lifetime of a variable within a program. There are typically two types of variable scope:

Local Scope:

A variable declared inside a function, block, or loop has a local scope.
It can only be accessed within the specific function, block, or loop where it is declared.
Its lifetime is limited to the duration of the function, block, or loop.

C++

#include <iostream>
using namespace std;

void myFunction() {
    // Variable with local scope
    int localVar = 10;
    cout << "Inside myFunction: " << localVar << endl;
}

int main() {

    myFunction();  // Calling the function

    return 0;
}

Java

public class Main {

    public static void myFunction() {
        // Variable with local scope
        int localVar = 10;

        // Accessing the local variable
        System.out.println("Inside myFunction: " + localVar);
    }

    public static void main(String[] args) {

        myFunction();  // Calling the function
    }
}

Python

def my_function():
    # Variable with local scope
    local_var = 10
    # Accessing the local variable
    print("Inside my_function:", local_var)

my_function()  # Calling the function

using System;

class Program
{
    static void MyFunction()
    {
        // Variable with local scope
        int localVar = 10;

        // Accessing the local variable
        Console.WriteLine("Inside MyFunction: " + localVar);
    }

    static void Main()
    {
        // Attempting to access the local variable from Main (not allowed)
        // Uncommenting the line below will result in a compilation error
        // Console.WriteLine("Inside Main: " + localVar);

        MyFunction();  // Calling the function
    }
}

Javascript

function myFunction() {
    // Variable with local scope
    let localVar = 10;
    console.log("Inside myFunction:", localVar);
}

// Calling the function
myFunction();

Output

Inside myFunction: 10

Global Scope:

A variable declared outside of any function or block has a global scope.
It can be accessed from anywhere in the program, including inside functions.
Its lifetime extends throughout the entire program.

C++

#include <iostream>
using namespace std;

// Variable with global scope
int globalVar = 20;

void myFunction() {
    // Accessing the global variable
    cout << "Inside myFunction: " << globalVar << endl;
}

int main() {
    // Accessing the global variable from main
    cout << "Inside main: " << globalVar << endl;

    myFunction();  // Calling the function

    return 0;
}

Java

public class Main {
    // Variable with class (global) scope
    static int globalVar = 20;

    public static void myFunction() {
        // Accessing the global variable
        System.out.println("Inside myFunction: " + globalVar);
    }

    public static void main(String[] args) {
        // Accessing the global variable from the main method
        System.out.println("Inside main: " + globalVar);

        myFunction();  // Calling the function
    }
}

Python

# Variable with global scope
global_var = 20

def my_function():
    # Accessing the global variable
    print("Inside my_function:", global_var)

# Accessing the global variable from the global scope
print("Inside global scope:", global_var)

my_function()  # Calling the function

using System;

class Program
{
    // Variable with global scope
    static int globalVar = 20;

    static void MyFunction()
    {
        // Accessing the global variable
        Console.WriteLine("Inside MyFunction: " + globalVar);
    }

    static void Main()
    {
        // Accessing the global variable from Main
        Console.WriteLine("Inside Main: " + globalVar);

        MyFunction();  // Calling the function
    }
}

Javascript

// Variable with global scope
let globalVar = 20;

function myFunction() {
    // Accessing the global variable
    console.log("Inside myFunction: " + globalVar);
}

function main() {
    // Accessing the global variable from main
    console.log("Inside main: " + globalVar);

    myFunction(); // Calling the function
}

main(); // Call the main function

Output

Inside main: 20
Inside myFunction: 20

Understanding and managing variable scope is crucial for writing maintainable and bug-free code, as it helps avoid naming conflicts and unintended side effects.

In conclusion, variables In programming are fundamental elements in programming, serving as named storage locations to hold and manipulate data. They are crucial in writing dynamic, adaptable, and functional code. The proper use of variables, adherence to clear naming conventions, and understanding of scope contribute to code readability, maintainability, and scalability.

Variable in Programming

In programming, we often need a named storage location to store the data or values. Using variables, we can store the data in our program and access it afterward. In this article, we will learn about variables in programming, their types, declarations, initialization, naming conventions, etc.

Variables in Programming

Table of Content

What are Variables In Programming?
Declaration of Variables In Programming
Initialization of Variables In Programming
Types of Variables In Programming
Difference between Variable and Constant
Difference between Local variables and Global Variables
Naming Conventions
Scope of a variable

Scope of a variable

Local Scope:

Global Scope:

Variable in Programming

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Scope of a variable

Local Scope:

Global Scope:

Variable in Programming

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