Function Overloading in C++

Last Updated : 12 Jan 2026

In C++, function overloading is a feature of object-oriented programming that enables multiple functions to have the same name but have distinct parameter lists (either in terms of type, number, or both). It makes the code more readable, reusable, and effective by allowing a function to handle different input types while maintaining a consistent interface. Function design is flexible because the compiler chooses the function to run based on the inputs supplied. It may be considered as an example of polymorphism in C++.

Syntax:

It has the following syntax:

return_type function_name(parameter1); 
return_type function_name(parameter2);

In this syntax, we have taken two function declarations that have the same name but different parameters:

Simple Function Overloading Example:

Let us take a program to illustrate the function overloading in C++.

Example

#include<iostream>
using namespace std; //using standard namespace

int sum(int a, int b) //Add two numbers
{
   return a + b;
}

int sum(int a, int b, double c) //Add three double numbers
{
   return a + b + c;
}

float sum(float a, float b) // Add two floating-point numbers
{
   return a + b;
}

int main() {
   cout<<sum(15, 20)<<endl;
   cout<<sum(5, 7, 9.4)<<endl;
   cout<<sum(5.7f, 8.4f)<<endl;

   return 0;
}

Compile and Run

Output:

35
21
14.1

Explanation:

In this example, we have taken three function declarations that contain the same name but different parameters.

How does Function Overloading Work in C++?

There are several steps that helps us to understand how function overloading works in C++.

Exact Match: First, the compiler looks for a function with the same name and an exact parameter match.
Implicit Conversion: If no exact match is found:
- The char, unsigned char, and short are converted to int.
- The float is converted to double.
Standard Conversion: If there is no match, C++ uses implicit type conversions to relsove it.
Compilation Error: If no suitable function is discovered after conversion attempts, a compilation error will result.

Types of Function Overloading in C++:

In C++, function overloading depends on the function name and the number or types of parameters. The return type alone cannot differentiate overloaded functions. If two functions have identical parameter lists but different return types, a compilation error occurs due to ambiguity. There are three types of function overloading, and they are:

Function Overloading Based on Number of Parameters.
Function Overloading Based on Different Parameter Types.
Function Overloading Based on Different Parameter Orders.

1. Function Overloading Based on Number of Parameters:

Function overloading can create multiple functions with the same name but different parameters. Depending on how many arguments are provided in during function calls, the compiler chooses the right function. It improves the code's readability, flexibility, and maintainability.

Syntax:

It has the following syntax.

void displayData(int value); // Function with 1 parameter.  
void displayData(int value, double rate); // Overloaded function with 2 parameters. 
void displayData(int value, double rate, string text); // Overloaded function with 3 parametes.

C++ Function Overloading Based on Number of Parameters Example:

A C++ program to illustrate Function Overloading Based on Number of Parameters.

Example

#include <iostream>
#include <string>
using namespace std; //using standard namespace

//Function with 1 parameter 
void printInfo(int age) 
{
    cout << "Age: " << age << " years" << endl;
}

//Function with 2 parameters 
void printInfo(int age, double height) 
{
    cout << "Age: " << age << " years, Height: " << height << " meters" << endl;
}

//Function with 3 parameters
void printInfo(int age, double height, string name) 
{
    cout << "Age: " << age << " years, Height: " << height << " meters," << " Name: " << name << endl;
}

int main() //main function
{
    printInfo(21); // function with 1parameter
    printInfo(28, 5.8); // function with 2 parameters
    printInfo(32, 6.2, "John"); //function with 3 parameters
    return 0;
}

Compile and Run

Output:

Age: 21 years
Age: 28 years, Height: 5.8 meters
Age: 32 years, Height: 6.2 meters, Name: John

Explanation:

In this example, we demonstrate function overloading by defining three printInfo functions with different parameter counts. It depends on how many arguments are passed. Each function prints information like age, height, and name.

Various versions of printInfo are called with one, two, and three arguments in the main function, which demonstrates how function overloading allows multiple functions with the same name but different parameters to exist.

2. Function Overloading Based on Different Parameter Types:

In this method, many functions have the same name but different data types for their parameters. It allows a function to handle a variety of inputs while retaining a consistent interface, which enhances the code readability and adaptability.

Syntax:

It has the following syntax.

void displayData(int num);  // integer parameter function  
void displayData(double num);  // double parameter function
void displayData(string text);  // a string parameter function.  

C++ Function Overloading Based on Different Parameter Types Example:

Example

#include <iostream>
using namespace std; //using standard namespace

void printInfo(int num) //int number

{
    cout << "An Integer value is: " << num << endl;
}

void printInfo(double num) //double function
{
    cout << "The Double value is: " << num << endl;
}

void printInfo(string text) //string function
{
    cout << "The String value is: " << text << endl;
}
int main() //main function
{
    printInfo(27); // Call a function with int number
    printInfo(7.36); // Call a function with double number
    printInfo("Hello TpointTech"); // Call a function with string
    return 0;
}

Compile and Run

Output:

An Integer value is: 27
The Double value is: 7.36
The String value is: Hello TpointTech

Explanation:

In this example, we demonstrate the function overloading based on different parameter types. The main function calls printInfo with various argument types, which triggers the appropriate function based on the argument's and data type. The application displays integer, double, and string values with corresponding labels.

3. Function Overloading Based on Different Parameter Order:

Function overloading allows many functions to share a name as long as the number, type, and order of the parameters in each function's list differ. Changing the order of the parameters while maintaining their types is known as overloading based on different parameter orders.

Syntax:

It has the following syntax.

void displayData(int x, double y) 
{
//code block
}
void displayData(double x, int y) 
{  
   //code block
}

C++ Function Overloading Based on Different Parameter Orders Example:

Example

#include <iostream>
using namespace std; //using standard namespace

void printInf(int a, double b) //int and double function
{
    cout << "Integer value is: " << a << ", Double value is: " << b << endl;
}

void printInfo(double a, int b) //double and int function
{
    cout << "Double value is: " << a << ", Integer value is: " << b << endl;
}
int main() 
{
    printInf(21, 5.4); // call int and double value
    printInf(7.84, 19); // Call double and int value
    return 0;
}

Compile and Run

Output:

Integer value is: 21, Double value is: 5.4
Double value is: 7.84, Integer value is: 19

Explanation:

In this example, we demonstrate function overloading by defining two printInf() methods with similar parameters but in different ordering. The first variant prints an integer ID and a double score, whereas the second variant prints a double rating and an integer count.

Use Cases for Function Overloading in C++:

Several use cases for function overloading in C++ are as follows:

Mathematical Operations: Overloading functions like calculate() for several parameter types (including int, float, and double) ensures precision and efficiency. It prevents loss of accuracy when performing arithmetic on different data types.
Handling Different Data Types: It improves code readability by enabling a single function name to handle several data types (including print(int), print(double), and print(string)).
Varying Number of Parameters: Functions (including logMessage(string), and logMessage(string, int)) are flexible enough to take different numbers of arguments.
Custom data processing: It allows for the specific handling of different data structures, such as sort(vector) and sort(vector). It enables the implementation of generic algorithms that handle many kinds of data.
Improving Code Maintainability: It reduces repetition and makes the code easier to manage and cleaner by combining related operations within a single function name. It increases reusability and reduces the possibility of errors brought on by the implementation of duplicate functions.

Main differences between Function Overloading and Operator Overloading

Several main differences between function overloading and operator overloading in C++ are as follows:

Function overloading	Operator overloading
It is possible to use various parameters in an overload of a function with the same name.	We can overload operators such as +, -, /
A function might have more than one execution with various parameters when it is overloaded.	Operation reliance on operands occurs when an operator is overloaded.
The user can call using a variety of methods.	In addition to the predetermined meaning, it enables the user to have a more expansive meaning.

Main differences between Function Overloading and Function Overriding:

Several main differences between function overloading and function overriding in C++ are as follows:

Function overloading	Function overriding
It allows the programmer to have many functions with the same name but distinct arguments.	Method overriding occurs when two methods with the same name and parameters are present in different classes, one in the parent and one in the child.
They have the same scope.	They have different scopes.
Even without inheritance, function overloading is possible.	It only happens when there is inheritance.

Next TopicFunction Overriding in C++

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Function Overloading in C++

Syntax:

Simple Function Overloading Example:

Example

How does Function Overloading Work in C++?

Types of Function Overloading in C++:

1. Function Overloading Based on Number of Parameters:

C++ Function Overloading Based on Number of Parameters Example:

Example

2. Function Overloading Based on Different Parameter Types:

C++ Function Overloading Based on Different Parameter Types Example:

Example

3. Function Overloading Based on Different Parameter Order:

C++ Function Overloading Based on Different Parameter Orders Example:

Example

Use Cases for Function Overloading in C++:

Main differences between Function Overloading and Operator Overloading

Main differences between Function Overloading and Function Overriding:

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Function Overloading in C++

Syntax:

Simple Function Overloading Example:

Example

How does Function Overloading Work in C++?

Types of Function Overloading in C++:

1. Function Overloading Based on Number of Parameters:

C++ Function Overloading Based on Number of Parameters Example:

Example

2. Function Overloading Based on Different Parameter Types:

C++ Function Overloading Based on Different Parameter Types Example:

Example

3. Function Overloading Based on Different Parameter Order:

C++ Function Overloading Based on Different Parameter Orders Example:

Example

Use Cases for Function Overloading in C++:

Main differences between Function Overloading and Operator Overloading

Main differences between Function Overloading and Function Overriding:

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