When it comes to inheritance in C++, there are three types that are commonly used: public, private, and protected. While public inheritance is the default type, private and protected inheritance are often used in specific situations. In this article, we will explore why private and protected inheritance are necessary in C++.
Firstly, let's understand what inheritance means in C++. In simple terms, inheritance allows a class to inherit the properties and behaviors of another class. This helps in code reusability and makes the code more efficient. However, there are certain scenarios where using public inheritance can lead to issues, and that's where private and protected inheritance come into play.
Private inheritance is a type of inheritance where the public and protected members of the base class become private members of the derived class. This means that the derived class can access these members, but they are not accessible to the outside world. Private inheritance is useful when we want to hide the implementation details of the base class from the outside world. It also helps in avoiding naming conflicts and reducing coupling between classes.
One of the main reasons for using private inheritance is to implement the "is-implemented-in-terms-of" relationship between classes. This means that the derived class is implemented in terms of the base class, and it is not a type of the base class. For example, let's say we have a class called "Shape" and a class called "Circle." If we use private inheritance, we are saying that a circle is implemented in terms of a shape, but it is not a type of shape. This allows us to use the functionality of the base class without exposing it to the outside world.
Protected inheritance, on the other hand, is a type of inheritance where the public and protected members of the base class become protected members of the derived class. This means that the derived class and its derived classes can access these members, but they are not accessible to the outside world. Protected inheritance is useful when we want to implement the "is-implemented-as-a" relationship between classes. This means that the derived class is implemented as a type of the base class. For example, let's say we have a class called "Animal" and a class called "Dog." If we use protected inheritance, we are saying that a dog is an animal and can access all the protected members of the animal class.
One of the main reasons for using protected inheritance is to restrict access to certain members of the base class. This is useful when we want to prevent the derived class from accessing certain public members of the base class, but we still want to give access to its derived classes. This helps in maintaining the integrity of the code and prevents any unintended modifications to the base class.
In conclusion, private and protected inheritance in C++ are necessary for maintaining the integrity of the code and implementing different types of relationships between classes. Private inheritance helps in hiding the implementation details of the base class, while protected inheritance helps in restricting access to certain members of the base class. Both types of inheritance have their own specific use cases and should be used accordingly. It is important to understand these concepts in order to write efficient and maintainable code in C++.
