Difference Between Overloading and Overriding

August 2022 · 5 minute read

In high-level languages, many coding techniques are implemented by coders to make the code more legible and simple. Moreover, many functions, constructors are also made in the program. Such functions and constructors can be either overloaded by different parameters or could be overridden. Let’s understand this in detail.

Overloading and overriding are two programming techniques used by programmers when writing code in high-level languages like C++, Java, Python, and others. Both strategies are effective in making the software less difficult. The overloading function is used to make the code more readable. However, the overriding method overwrites the parent class.

Overloading vs Overriding

The main difference between overloading and overriding is that the overloading function is used in the same class (a concept in computer languages). On the other hand, the method of one class is inherited by the other class under overriding. It indicates that the same method is passed from the main class to the subclasses.

Overloading entails writing the same functions many times with different parameters. However, we can’t do this in the C programming language. Otherwise, Java supports the concept of overloading. Three types of overloading can be done by programmers while coding in Java. It is a useful concept to make the program simple.

In computer language, an overriding method is utilized in the concept of inheritance. Whenever a function is created in the superclass and then used in a subclass by inheriting the main class’s methods. It allows the subclass to override the parent class’s function since the subclass has priority when the program runs.

Comparison Table Between Overloading and Overriding

Parameters of ComparisonOverloadingOverriding
PurposeTo overload the same function.Using the parent class’ methods to the subclass.
UsedOverloading occurs in the same class or even in different ones too.Overriding is done in separate classes having inheritance relation.
ParametersThe parameters are different from each other.Parameters are the same in both subclass and superclass.
Return TypeUnder overloading, the return type can be either the same or different.Under overriding, the return type should be the same.
PolymorphismSince one function can take distinct parameters in overloading at compile time. So, it is compile-time polymorphism.Overriding is also known as run time polymorphism.

What is Overloading?

Overloading refers to overloading the same method several times. In C language, we can’t overload functions. However, in Java, we can overload in three ways. The types are construction overloading, method overloading, and operator overloading.

When a programmer reuses the same code, the arguments are changed every time. It is known as underloading. Default overloading (definition of the same function without any parameters) and parameter overloading (defining a function with parameters) are both possible.

The operator (+) is defined for both addition and concatenation (linking) in the case of operator overloading. Furthermore, the return type of the parameters does not have to be the same.

The process of overloading is known as polymorphism (using the same thing in a separate form while compiling). As a result, it’s referred to as compile-time polymorphism.

Example of a constructor overloading

Class X

{

Int a;

X (),

{

a= 10;

}

X (int x);

{

a=x;

}

}

Class Y

{

public static void main (args)

{

X obj= new X();

X obj1= new X(100);

System.out.println(obj.a” “);

System.out.println(obj1.a” “);

}

}

In the above example, constructor X appears twice. The first time there was no argument, and the second time there was a parameter. Distinct objects (obj, obj1 ) exist to tell values. Similarly, one can use functions and operators in the overloading concept.

What is Overriding?

Under the class inheritance, programmers use method overriding (when properties of one class are inherited into another one). If a subclass or child class is dissatisfied with the execution of the superclass’s or parent’s methods while inheriting, the subclass can override its function.

For overriding, method or function in both the class should be the same along with the parameters defined. In addition, the return type and scope should be identical in both classes.

However, there are two limitations to overriding. The first is that the coders cannot override a super class’s static function. Another disadvantage is if the function’s type in the main class is declared as final. In a sub-class, it is not possible to override it.

Let’s understand with an example:

Class Super

{

void show();

{

system.out.println(” OVERRIDE”);

}

}

Class Sub extends Super

{

void show();

{

system.out.println(” OVER”);

}

}

Class override

{

public static main (string[], args())

{

Sub s= new Sub();

s.show ();

}

}

The output of the above example will be (OVER). It signifies that only the output of a subclass will appear because subclass (Sub) has overridden superclass (Super). No results of the main class will be there. Moreover, function (show) has the same return type, scope, and arguments.

Main Differences Between Overloading and Overriding

  • Overloading can occur inside a single class or across multiple classes. To override the function, we must create at least two classes.
  • Overloading is not possible in the C programming language. However, overriding is not feasible when one of the main class’s functions is static or final.
  • Overloading is also known as compile-time polymorphism. On the other hand, overriding is done at run time (known as run time polymorphism).
  • The return type can change while the program is being executed with overloading. When employing overriding, however, this is not possible.
  • Overloading makes the program easy for coders. On the contrary, overriding is done if the coder is not satisfied with the values of the main class.
  • Conclusion

    Multiple techniques or methods are available for the developer while making an application. The methods can be used at either compile-time (during the transformation of source code into the intermediate code) or runtime (to run the code).

    Overloading is a vital concept in languages such as Java. With the help of overloading, function, constructors, and operators no longer have to be defined each time with the new name. One can utilize the same methods by passing different arguments. With the help of overriding, the coder can redefine the function in subclasses if he feels that function of the parent class is not satisfactory.

    References

  • https://link.springer.com/chapter/10.1007/978-3-642-14107-2_25
  • https://dl.acm.org/doi/abs/10.1145/1141277.1141608
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