Difference between function overloading and function overriding in C++

Both function overloading and function overriding are essential in object-oriented programming (OOPs) for enabling code reuse and flexibility. The two ideas are fundamentally different, despite the fact that they could sound identical. The goal of this blog is to give readers a thorough understanding of C++ function overloading and function overriding. To demonstrate these differences, we will look at their definitions, syntax, code samples, and output. We'll also give a tabular comparison to highlight the differences between the two ideas.

Function Overloading:

The C++ language's function overloading feature enables numerous functions with the same name to coexist if they each have unique parameters. It makes it possible for programmers to execute related operations on a variety of data types or argument lists. The number, kind, and order of the arguments help the compiler identify these overloaded functions.

Syntax:

The following is the syntax for function overloading:

Example:

#include <iostream>

void print(int num) {
std::cout<< "Printing integer: " << num <<std::endl;
}

void print(double num) {
std::cout<< "Printing double: " << num <<std::endl;
}

int main() {
print(10);
print(3.14);
    return 0;
}

Output:

Printing integer: 10
Printing double: 3.14

Explanation:

In the above example, we defined two print-related functions. While the second print function requires a double parameter, the first print function only needs an integer argument. Based on the types of arguments, the compiler distinguishes between the two functions. The function with the integer parameter is called when we use print(10), and it prints "Printing integer: 10". For this, when we use print(3.14), the double Para metered function is called and prints "Printing double: 3.14".

Function Overriding:

Function overriding is a term used in inheritance, where a derived class implements a base class method in a unique way. It enables polymorphism and permits objects of various classes to be handled consistently when accessible via a pointer or reference to a common base class.

Syntax:

The following is the syntax for overriding a function:

class Base {
public:
    virtual return_typefunction_name(arguments) {
        // Base class implementation
    }
};

class Derived : public Base {
public:
return_typefunction_name(arguments) {
        // Derived class implementation
    }
};

Example:

#include <iostream>

class Shape {
public:
    virtual void draw() {
std::cout<< "Drawing a shape." <<std::endl;
    }
};

class Circle : public Shape {
public:
    void draw() {
std::cout<< "Drawing a circle." <<std::endl;
    }
};

int main () {
    Shape* shape = new Circle();
    shape->draw();
    delete shape;
    return 0;
}

Output:

Drawing a circle.

Explanation:

In the above example, we have a base class called Shape and a derived class called Circle. A method called draw() exists in both classes. The implementation of the basic class only prints "Drawing a shape". The derived class provides a different implementation of this method that prints "Drawing a circle". We build a Circle object and assign it to a Shape pointer in the main() function. The overridden function in the Circle class is called when we call the draw() method through the base class reference, and it prints "Drawing a circle".

Head-to-head comparison between Function Overloading and Function Overriding

Here, you will learn the head-to-head comparisons between function overloading and function overriding. The main differences between function overloading and function overriding are as follows:

Aspect	Function Overloading	Function Overriding
Scope	Same class	Base and derived classes
Inheritance Required	No	Yes
Arguments	Different parameters	Same parameters
Polymorphic Behavior	No	Yes
Dynamic Binding	No	Yes

Scope:

Function overloading: The same class contains overloaded functions.

Function overriding: Both base and derived classes have overridden functions.

Inheritance Required:

Function Overloading: It has no need for inheritance. Within the same class, overloading can take place.

Function Overriding: It necessitates inheritance. The function that will be overridden in the derived class must be defined in the base class.

Arguments:

Function overloading: Within the same class, overloaded functions may have distinct parameter lists (number, type, or sequence).

Function Overriding: In both base and derived classes, overriding functions have the same argument list (number, type, and sequence).

Polymorphic Behavior:

Function overloading: Polymorphic behavior is not displayed by overloaded functions. The arguments supplied determine the suitable function at compilation time.

Function overriding: Polymorphic behavior is made possible via overridden functions. The real object type determines the appropriate function at runtime.

Dynamic Binding:

Functional Overloading: No dynamic binding is necessary. The compiler decides which overloaded function to use at compile time based on the inputs.

Function overriding: Dynamic binding is used with overridden functions. Polymorphism is made possible by the runtime selection of the appropriate function based on the actual object type.

Compiler Resolution:

Function Overloading: Based on the arguments given to the function call, the compiler handles function overloading at compile time.

Function Overriding: Dynamic binding is used to resolve function overriding at runtime.

Explanation:

Scope:

Overloading of functions happens within the same class. In a same class, various functions with the same name but different parameters can coexist. It makes it possible for developers to execute related actions on various data types or with diverse argument lists.

Both base classes and derived classes support function overriding. A method that is already defined in the base class is provided with a customized implementation by the derived class. It enables objects of various classes to be handled consistently when accessible via a pointer or reference to a common base class.

Inheritance Required:

Overloading of functions does not need inheritance. Within the same class, overloaded functions might exist without any connection to one another.

However, function overriding needs inheritance. The function that will be overridden in the derived class must be defined in the base class. The function is inherited by the derived class from the base class, and it offers its own implementation.

Arguments:

Function overloading is the definition of numerous functions within the same class with the same name but distinct argument lists. The parameters can vary in terms of quantity, kind, or order. It offers flexibility in carrying out similar procedures with other arguments or data kinds.

The overridden function in the derived class must have the same argument list as the corresponding function in the base class to be considered a function override. The parameters must absolutely match in terms of quantity, category, and order. When using base class pointers or references to call the function, it guarantees consistency in behavior.

Polymorphic Behavior:

The behavior of function overloading is not polymorphic. The arguments given to the function call are used to find the suitable overloaded function at build time. Without taking the actual object type into consideration, the selection is decided statically.

Polymorphic behavior is enabled by function overriding. Through base class pointers or references, it enables uniform treatment of objects of various classes. Based on the actual object type, the suitable overridden function is decided upon at runtime. This dynamic coupling promotes extension and runtime flexibility.

Dynamic Binding:

Dynamic binding is not a part of function overloading. The compiler decides at compile time which overloaded function is the most suited. Based on the arguments supplied during the function call, it chooses which function to invoke.

Dynamic binding is used in function overriding. At runtime, the appropriate overridden function is chosen. The choice is made depending on the actual object type, which supports runtime polymorphism and late binding.

Compiler Resolution:

The compiler handles function overloading at compile time. Based on the quantity, kind, and order of the parameters, the compiler matches the arguments given to the function call with the relevant overloaded function.

On the other side, function overriding is resolved in-place. Based on the actual object type, the suitable overridden function is chosen dynamically. Virtual function tables and virtual function pointers are used in the background to accomplish this runtime resolution.

Conclusion:

In summary, function overloading and function overriding are two crucial C++ features that improve the flexibility and reuse of code. Although their syntax and the idea of having several functions with the same name may be similar, there are significant distinctions between the two.

Programmers can define numerous functions with the same name but distinct argument lists within the same class by using function overloading. As a result, the proper function can be chosen at compile time based on the arguments supplied. By enabling the execution of equivalent operations on other data types or with varied argument lists, it offers simplicity and versatility.

On the other hand, polymorphism and inheritance both employ function overriding. It happens when a method that is already specified in the base class is implemented by a derived class on its own. It enables objects of various classes to be handled consistently when accessible via a pointer or reference to a common base class. Dynamic binding is demonstrated via function overriding, which means that the right method is chosen at runtime based on the actual object type.

It's essential to comprehend the differences between function overloading and function overriding while building effective, maintainable C++ code. Developers can build sturdy, adaptable programs that satisfy various needs and encourage code reuse by wisely utilizing these qualities.

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