What is the Use of Function Overloading in C++?

If you want to remember something for life, find the why behind it.

We hear a lot about function overloading. But hardly many know why it is important and what is the use of it.

I have taken 100s of interviews, when I ask candidates about function overloading. Everyone tells me about it.

But when I asked why we need function overloading, even the candidate having 7+ years of experience doesn’t have an answer.

If you don’t know the practical use, your technical knowledge has zero value.

What is function overloading in C++?

Function overloading in C++ allows you to define multiple functions with the same name but different parameter lists within the same scope.

This provides flexibility by enabling a function to perform different tasks based on the number or types of its parameters.

Use of Function Overloading in C++?

Let’s say you have to write a function to find the average of two numbers (says get_average()).

#include <iostream>

double get_average(double num1, double num2) {
    return (num1 + num2) / 2.0;
}

int main() {
    double average = get_average(34, 56);
    std::cout << "Average of two numbers: " << average << std::endl;
    return 0;
}

Output:

Average of two numbers: 45

You can write another function with the same name to find the average of the array.

#include <iostream>

// 1st fuction to find the average of two numbers
double get_average(double num1, double num2) {
    return (num1 + num2) / 2.0;
}

// 2nd fuction to find the average of array
double get_average(const double arr[], int size) {
    double sum = 0.0;
    for (int i = 0; i < size; ++i) {
        sum += arr[i];
    }
    return sum / size;
}

int main() {
    //Calculate the average of two numbers
    double average_num = get_average(34, 56);
    std::cout << "Average of two numbers: " << average_num << std::endl;

    // Initialize an array with predefined values
    const int size = 5;
    double numbers[size] = {10.5, 20.5, 30.5, 40.5, 50.5};


    // Calculate the average of array of numbers
    double average_array = get_average(numbers, size);

    std::cout << "Average of array: " << average_array << std::endl;
    return 0;
}

Output:

Average of two numbers: 45
Average of array: 30.5

While calling a function if you pass two integers, the first function is called. If you pass an array of numbers to find the average, a second function will be called.

It enhances code readability and makes it more intuitive for developers to use the same function name with similar purposes.

I tried to explain it with very simple examples. If you have any doubts or want to share your thoughts, write in the comment section below.

Aniruddha Chaudhari

I am complete Python Nut, love Linux and vim as an editor. I hold a Master of Computer Science from NIT Trichy. I dabble in C/C++, Java too. I keep sharing my coding knowledge and my own experience on <b>CSEstack.org</b> portal.