Reference Variable is a reference to an existing variable, which is defined with the help of the & operator. In other words, reference variables are aliases of some existing variables, and then either of the two variables can be used. Updating the reference variable is same as updating the original variable.

Reference variable in C++:

In C++, the term “reference variable” refers to a variable that acts as an alias for another variable. Unlike pointers, which store addresses, reference variables directly refer to the variable they are bound to. Once initialized, a reference variable cannot be reseated or made to refer to another variable.

Below is the implementation of Reference variable in C++:

#include <bits/stdc++.h>
using namespace std;
int main()
{
    string name = "GeeksforGeeks";
    string& referenceVar = name;

    // Changes made to the reference variable is same as
    // changes made to original variable
    reverse(referenceVar.begin(), referenceVar.end());
    cout << "name = " << name << "\n";
    cout << "referenceVar = " << referenceVar << "\n";

    return 0;
}

name = skeeGrofskeeG
referenceVar = skeeGrofskeeG

Reference variable in Java:

In Java, we can access an object only through reference variable. A reference variable is declared as a special data type and this data type can never be changed. Reference variables can be declared as static variables, instance variables, method parameters, or local variables. A reference variable that is declared as final cannot be reassigned as a reference to another object. In this, the data inside the object can be changed, but the reference variable cannot be changed.

Below is the implementation of Reference Variable in Java:

public class ReferenceVariableDemo {
    public static void main(String[] args) {
        // Declare and initialize reference variables
        String[] languages = {"Java", "C++", "Python"};
        String[] ref = languages;

        // Modify data through reference
        ref[2] = "JavaScript";

        // Print original array
        System.out.println("Original Array:");
        for (String lang : languages) {
            System.out.println(lang);
        }

        // Print modified array through reference
        System.out.println("\nModified Array:");
        for (String lang : ref) {
            System.out.println(lang);
        }
    }
}

Original Array:
Java
C++
JavaScript

Modified Array:
Java
C++
JavaScript

Reference variables are a basic concept of programming, through which a programming element is assigned a “reference” to data or memory. Learning the way these reference variables are built, used, benefits, and the techniques to make them work correctly can see developers using the variables to develop independent, strong, and superior software for use in various programming languages.