C++ FAQ Celebrating Twenty-One Years of the C++ FAQ!!!
(Click here for a personal note from Marshall Cline.)
Section 19:
19.1 Is inheritance important to C++?
19.2 When would I use inheritance?
19.3 How do you express inheritance in C++?
19.4 Is it OK to convert a pointer from a derived class to its base class?
19.5 What's the difference between public, private, and protected?
19.6 Why can't my derived class access private things from my base class?
19.7 How can I protect derived classes from breaking when I change the internal parts of the base class?
19.8 Protected data vs. private data with protected access functions?
19.9 Okay, so exactly how should I decide whether to build a "protected interface"?
[19.5] What's the difference between public, private, and protected?
  • A member (either data member or member function) declared in a private section of a class can only be accessed by member functions and friends of that class
  • A member (either data member or member function) declared in a protected section of a class can only be accessed by member functions and friends of that class, and by member functions and friends of derived classes
  • A member (either data member or member function) declared in a public section of a class can be accessed by anyone