Data hiding in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is data hiding in C++?

Data hiding is a technique to restrict direct access to some of an object's components, usually by making data members private or protected. It helps protect the internal state of an object from unintended changes.

beginner

Which access specifier is used in C++ to hide data members from outside access?

The private access specifier hides data members so they cannot be accessed directly from outside the class.

intermediate

Why is data hiding important in object-oriented programming?

Data hiding helps maintain control over how data is accessed or modified, prevents accidental corruption of data, and supports the principle of encapsulation by exposing only necessary parts of an object.

beginner

How can you provide controlled access to hidden data members in C++?

You can provide controlled access by defining public member functions called getters and setters that read or modify private data members safely.

beginner

Consider this code snippet:<br><pre>class Box {
private:
  int length;
public:
  void setLength(int len) { length = len; }
  int getLength() { return length; }
};</pre><br>What concept does this demonstrate?

This demonstrates data hiding by making length private and providing public methods to access and modify it safely.

Which access specifier hides data members from outside the class in C++?

A private

B public

C protected

D internal

The private specifier hides members from outside access.

What is the main purpose of data hiding?

A To protect data from unintended access or modification

B To allow direct access to all data

C To make code run faster

D To increase the size of the program

Data hiding protects data by restricting direct access.

How do you usually access private data members from outside a class?

A Using friend functions only

B Directly using the dot operator

C Using public getter and setter functions

D You cannot access them at all

Public getter and setter functions provide controlled access.

Which of these is NOT an access specifier in C++?

A private

B hidden

C protected

D public

hidden is not a valid access specifier in C++.

What keyword is used to declare a class member that can be accessed by derived classes but not by other code?

A private

B public

C internal

D protected

The protected specifier allows access in derived classes only.

Explain what data hiding is and why it is useful in C++ programming.

Think about how you keep your personal information safe and only share what is necessary.

Describe how you can safely allow other parts of a program to read or change private data members.

Imagine giving a friend a key to your house but only for certain rooms.