Everything you need to know about Inheritance in programming
Tags: coding, java
Published: 2023-12-30 18:49:41

The use of Inheritance helps to save time and effort in programming a new class that is similar to an existing class in behaviour. 

Inheritance is a fundamental concept in programming that allows you to create new classes based on existing classes. It enables code reuse and promotes the concept of hierarchical relationships between classes.

There are different types of inheritance in programming, including single, multi-level, multiple, multipath, hierarchical inheritance and hybrid inheritance. 

However, not all types of inheritance apply to all the programming languages like multiple inheritance in Java is not supported as it can lead to a diamond problem. 

Let’s go deeper and learn everything about Inheritance in programming, its types, advantages and disadvantages in this blog.

## What is Inheritance in Programming?

Inheritance is a widespread mechanism in programming that allows the creation of new classes based on existing ones. If you want to create a new class with similar characteristics to an existing class. Then here's how Inheritance can help you. 

With the help of Inheritance, you can inherit all the properties and methods of an existing class to the new one. Now, you can keep editing the new class that was not present in the existing class. 

Moreover, there are a few terms and synonyms that one should know about. First, the class from which the new class is inherited is called the Superclass or parent class. At the same time, the new class is called the Sub class or child class.
 

## What are the types of Inheritance?

Many types of Inheritance are used for different purposes. Below are the types of Inheritance in programming and their implementation. 

Single Inheritance

Single Inheritance is the most straightforward type of Inheritance. A child class inherits properties and methods from a single-parent class. The child class extends the parent class and can add or change its properties and methods. Single Inheritance creates a simple and linear hierarchy; thus, each class has only one parent. It is used in many programming languages, including Java and C++.

Multiple Inheritance

Multiple Inheritance is where a child class inherits properties and methods from multiple parent classes. A child class can extend two or more parent classes in this type of inheritance. Multiple Inheritance creates a complex hierarchy where each class can have multiple parents. Although, it is powerful but can be challenging to implement and maintain. 

Note: It is not possible to use [multiple Inheritance in Java](https://www.codingninjas.com/studio/library/multiple-inheritance-in-java). However, it can be used in other languages like C++ and Python.

Hierarchical Inheritance

In hierarchical Inheritance, a child class inherits properties and methods from a single-parent class. In this, multiple child classes can inherit from the same parent class. Hierarchical Inheritance creates a hierarchical structure. Here each class has a single parent and multiple children.

Multilevel Inheritance

In multilevel Inheritance, a child class inherits properties from a parent class. Also, the same child class becomes a parent class for another child. In multilevel Inheritance, each child class is a parent class for the next child class. Hence, this creates a multilevel hierarchy. 

Hybrid Inheritance

Hybrid Inheritance is a mix of multiple and hierarchical Inheritance. A child class inherits properties and methods from multiple parent classes. In addition, multiple child classes inherit from the same parent class. This type of Inheritance is powerful but challenging to implement and maintain.

## What are the Advantages of Inheritance?

There are several advantages of Inheritance. Let us look at some of the most important advantages of Inheritance. 

Code Reusability
Inheritance allows you to reuse existing code and functionality. It can save you a lot of time and effort in the development process. Inheriting properties from existing classes can help you build new classes. Hence, while building new classes, you can use lesser code. 


Improved Code Organization
Inheritance promotes code organization by grouping related classes together. It creates a hierarchy of classes that share common attributes and behaviours. Hence, you can better the organize your code and make it easier to maintain and update.

Flexibility and Modularity
Inheritance provides flexibility and modularity. It does so by allowing you to extend and change existing classes. Inheritance does not affect the class's original implementation. By inheriting from a base class, you can add new functionality. You can even change existing functionality independent of the original implementation.

Polymorphism
Inheritance enables polymorphism. Objects can take on different forms depending on their context. You can use polymorphism to create more flexible and extensible code.

Simplified Maintenance
Inheritance simplifies maintenance. It reduces the amount of code that needs to be updated when changes are made. You can make changes to the base class, and it will automatically propagate to all derived classes.
 

## What are the Disadvantages of Inheritance

Inheritance can be a powerful tool in object-oriented programming. However, it also has several drawbacks that developers should be aware of. Here are some of the main disadvantages of Inheritance:

Tight Coupling
Inheritance creates a tight coupling between parent and child classes. Any changes to the parent class can affect the child class and vice versa. This can make it challenging to maintain and change code over time.

Inflexibility
Inheritance can also make code inflexible. This is because changes made to the parent class may not get reflected in the child class. This can make it difficult to adapt to changing requirements or add new features to the code.

Overuse 
Another disadvantage of Inheritance is that it can be overused. This leads to overly complex code. In some cases, it may be better to use composition (where objects get composed of other objects) instead of Inheritance.

Method overriding
When a child class overrides something from the parent class, it can lead to unexpected behaviour. This usually happens if the child class does not correctly implement the method. This can result in bugs and other issues that are difficult to debug.

Name clashes
Inheritance can also lead to name clashes. Two or more classes with methods or attributes with the same name can cause ambiguity. Also, this makes it difficult to determine which method or attribute should be used.

Understanding the concept of inheritance is vital to even cracking a coding interview. While practising for any type of coding interview questions; like, [SQL query interview questions](https://www.codingninjas.com/codestudio/library/sql-interview-questions), do not forget to practice the important questions related to inheritance. 


## Final Words
Inheritance is a valuable programming mechanism. It facilitates code reuse, organization, flexibility, modularity, and maintenance. But, it has two or more classes with flexibility, overuse, and method overriding. Every programmer should comprehend this fundamental concept for efficient and maintainable code. It is one of the most important ways to save time and effort while coding.