Inheritance in C++: Public, Private, Protected, and Inheritance Hierarchy

In Object-Oriented Programming (OOP), inheritance is an important concept. C++, as a language that supports OOP, offers various types of inheritance to help programmers create clear and maintainable code structures. This article will detail the different types of inheritance in C++ classes, including public, private, protected, and how they form a complete inheritance hierarchy.

1. Basic Concepts

1.1 Inheritance

In C++, classes can be extended in a “base class – derived class” manner. The derived class can inherit properties and methods from the base class, thereby reusing existing code and implementing more complex data models.

1.2 Public, Private, and Protected Inheritance

C++ provides three access control modes to define the visibility of base class members in derived classes:

Public: Public members in the base class will remain public in the derived class.
Private: Public and protected members in the base class will become private and cannot be accessed directly in the derived class.
Protected: Public and protected members in the base class will remain protected in the derived class, allowing access to further derived subclasses.

Understanding these different types is crucial as they dictate how you design your program and the level of data encapsulation.

2. Example Code

Here is a simple example illustrating the different types of inheritance and their effects:

#include <iostream>using namespace std;
// Base class - Animalclass Animal {public:    void sound() {        cout << "Animal makes a sound" << endl;    }    protected:    void eat() {        cout << "Animal is eating" << endl;    }};

// Public inheritanceclass Dog : public Animal {public:    void bark() {        cout << "Dog barks" << endl;        sound(); // Call public function from base class        eat();   // Call protected function from base class    }};

// Private inheritanceclass Cat : private Animal { // All Animal methods are now private and cannot be reused below 
public:    void meow() {        cout << "Cat meows" << endl;                // sound(); Not allowed, cannot access sound()        // eat(); Not allowed, cannot access eat()                // Can still use methods derived from Cat                 Dog d;           d.bark();     }};

// Protected superclass overrideclass Puppy : protected Dog {      public:      void testPuppy(){             bark();             eat();                  }     };

int main() {    Dog dog;    dog.bark();
    Cat cat;    cat.meow();
   Puppy puppy;    puppy.testPuppy();
   return 0;}

Example Explanation

Animal is our base class, which contains the public function sound() and the protected function eat().
The Dog class inherits publicly from Animal, so it can freely call its parent’s methods, including higher-privileged methods like eat() and sound().
In contrast, the Cat class inherits privately from Animal. Once this is done, you cannot directly call any of the inherited parent type’s methods through instantiated objects, reflecting our opaque handling logic of subsets or their behaviors being consistent and predictable. However, they still exist in the internal implementation, but external tracking of processing logic is required.
The final example shows the reading usage—applying a breakdown rather than changing object control or limiting the instruction flow when generating new computational events. This allows reinforcement, preserving the foundational information, which is why summarizing things enables you to recreate many similar structures with absolute interconnectivity, by granting original marginal privilege operations to further customize needs, and implicitly integrating target delivery into the environment, where the acquired details must dynamically facilitate awareness growth in solving distant node issues.

Conclusion

Understanding the continuously evolving responsibilities of C++ due to its multiple inheritance mechanisms and structuring communication depth will significantly enhance coding efficiency. Meanwhile, flexibly and effectively applying evaluative coefficients is undoubtedly a key consideration in minimal concern planning. We hope this article helps you grasp the various new accurate benefits of different forms in C++, meeting the historical efficiency of common alternative phenomena traditionally associated with total net amounts involved. Happy coding!