C++ class inheritance, key concept

What’s inherited

All base class members are inherited to derived class, except for:

1. its constructors and its destructor
2. its assignment operator members (operator=)
3. its friends

Note: private members are inherited but not directly accessible by the derived class.

Inheritance access specifier

1. public: mostly used. Allows the derived class to access public and protected members of the base class.
2. protected: turns public members of the base class to potected.
3. private: turns public and protected members of the base class to private.

Order of execution

• Constructor: First base class then derived class
• Destructor: First derived class then base class

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Code Example

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Explanation

Class Parent:

• Contains a private member privateMember and a public member publicMember.
• Defines a default constructor that initializes these members and prints a message.
• Defines a destructor that prints a message.
• Provides a public member function getPrivateMember() to access the private member.

Class Child1:

• Publicly inherits from Parent.
• The public inheritance allows Child1 to access the public members of Parent.
• Defines a constructor and destructor that print messages.

Class Child2:

• Privately inherits from Parent.
• The private inheritance means the inherited public members of Parent become private members of Child2.
• Defines member functions getParentPublicMember() and getParentPrivateMember() to access the inherited members.
• Defines a constructor and destructor that print messages.

Main Function:

• Creates objects of Child1 and Child2.
• Demonstrates access to public members and member functions of the parent class through child objects.
• Shows the order of constructor and destructor calls.

Conclusion

Understanding access specifiers and inheritance is crucial for designing robust and maintainable object-oriented programs in C++. Constructors and destructors help manage the lifecycle of objects, ensuring proper initialization and cleanup.