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Abstract Classes in C++: Creating Frameworks for Code Reusability

Definition of Abstract Classes in C++

Well, a C++ abstract class comes with at least one pure virtual function. This means that neither these classes nor a function without a definition can be instantiated. To prevent the child class from becoming an abstract class in and of itself, the abstract class’s child classes must give the body to the pure virtual function. 

Table of Content —

• Definition of abstract classes in C++
• Purpose of abstract classes in C++
• Abstract Classes vs. Concrete Classes
• Creating Abstract Classes in C++
• Benefits of Abstract Classes in C++
• Comparing abstract classes with interfaces in C++
• Examples of abstract classes in C++
• FAQs

Purpose of Abstract Classes in C++

Broad notions are expressed using an abstract class in C++, from which more specific classes can be descended. It is not possible to create an abstract class-type object. However, you can utilize pointers and references to abstract class types. 

Create an abstract class with a minimum of one pure virtual member feature. Enforcing polymorphism is another objective of abstract classes. The capacity to treat objects of various types similarly is known as polymorphism. 

A base class that incorporates abstract classes and specifies a common interface for a set of derived classes can be created. After that, you can refer to any objects of derived classes using pointers or references to the base class. 

Learn More: Hierarchical Inheritance In Java

Abstract Classes in C++ vs. Concrete Classes

Below is the quick comparison of Abstract class in C++ Vs concrete classes:

Creating Abstract Classes in C++

Here’s how to create an abstract class in C++:

Implementing Concrete Classes

Concrete class implementation in C++ is a rather simple procedure. Firstly, define the class. The class definition should outline the class’s data members and member functions. Implementing the class’s member functions is the next step. 

Finally, you may use a concrete class object to engage with the outside world. Concrete class implementation in C++ is a potent technique for producing reusable and maintainable code. 

Understanding Polymorphism and Its Relationship to Abstract Classes

The idea of polymorphism is especially useful when dealing with a single abstract term implemented in various forms. You can design a single abstract class using polymorphism and modify it to fit your techniques and ideas. 

For instance, describe the common methods and properties shared by all shapes in Shape’s abstract class. Subclasses of Shape might then be created for other shapes, like a Circle, a Rectangle, and a Triangle. Since it cannot be instantiated, the Shape class would be abstract. 

On the other hand, the Shape class’s subclasses may all be instantiated and have access to the same functions and attributes. This would enable you to treat all shapes equally, even though they can be different. 

When it comes to OOP, a C++ abstract class serves the purpose of a powerful and efficient tool for achieving polymorphic behavior. Subclasses that can differ in how they specifically implement a common behavior can be made by declaring that behavior in a C++ abstract class. 

As a result, you may design code that can be applied to various object types without worrying about how the behavior would be implemented specifically. 

As an illustration, you could develop the general behavior of all shapes into an abstract class named Shape. Methods for drawing the shape and figuring out its area and perimeter could all be a part of this behavior. 

After that, you may make subclasses of Shapes for particular forms like Circles, Rectangles, and Triangles. Each of these subclasses would implement the common functionality of Shape in a manner unique to the type of shape it represents. 

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Benefits of Abstract Classes in C++

Below are the key benefits of Abstract class in C++ for your better understanding:

• Reusability: Code reuse is possible with abstract classes. You save time, energy, and effort as you won’t have to rewrite the existing code. 
• Abstraction: Implementation specifics can be abstracted away using abstract classes. This may make it simpler to read and update your code. 
• Polymorphism: It can be implemented by using the C++ abstract class. Your code may become more expandable and adaptable as a result. 
• Error Checking: An abstract class in C++ may require error-checking to reduce coding errors. 
• Code Documentation: Abstract classes can be used as a tool for code documentation. This may make it simpler to read and update your code. 

Comparing Abstract Classes with Interfaces in C++

Examples of Abstract Classes in C++

Consider creating a calculator that outputs the perimeter when a shape is entered. Think about the kind of code you would implement in such a calculator. You can start with a few fundamental forms and hardcode the perimeter if you create unique functions inside the Shape class. That’s how the class might show up on display:

Conclusion

An effective tool for building frameworks for code reuse is abstract classes. You can provide a group of classes with a common interface and require subclasses to implement specific methods by utilizing abstract classes. 

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