Question

When you define an ADT as a C++ class, should you make the member variables public or private? Should you make the member functions public or private?

Short answer

In general, when defining an ADT using a C++ class, member variables should have the private access specifier to ensure data encapsulation, and member functions should mainly have the public access specifier, allowing external parts of the program to interact with the ADT. However, private member functions may be used internally by the class as needed.

Step-by-step solution

Understanding Access Specifiers in C++ Classes

Access specifiers determine the scope and visibility of class members (variables and functions) in C++ programming. The main access specifiers are public, private, and protected. Public members are accessible from any part of the program, private members can only be accessed within the class, and protected members can be accessed within the class and its subclasses.

Deciding on Access Specifiers for Member Variables

In an ADT (Abstract Data Type) implementation using a C++ class, it's common practice to make the member variables private. Making member variables private ensures data encapsulation and prevents accidental modification of the data from external parts of the program. By keeping member variables private, we maintain a clear separation of concerns between the interface and the implementation of the ADT.

Deciding on Access Specifiers for Member Functions

Member functions should generally be made public, especially if they form part of the interface used by external code to interact with the ADT. Making member functions public allows external parts of the program to use these functions to perform operations on the data within the class. In some cases, you may also have private member functions that are used internally by the class, which should not be accessible from external parts of the program.

Conclusion

When defining an ADT as a C++ class, you should make member variables private and the member functions mainly public (with private functions used internally as needed). This approach ensures proper data encapsulation and provides a clean interface for interacting with the ADT.