C++ Access Specifiers - Curated by Rajat Kumar

The Three Levels of Access

Think of a class like a building. Different areas have different rules about who can enter.

Real Life Analogy: Public Park

public

Public

Accessible from anywhere. Like a park, anyone can walk in.

check Inside the class
check In derived classes
check External functions (main)

Real Life Analogy: Bank Vault

lock

Private

Accessible ONLY within the class. Strictly confidential.

check Inside the class
close In derived classes
close External functions (main)

Analogy: Family Inheritance

shield_person

Protected

Accessible in the class AND by children (derived classes).

check Inside the class
check In derived classes
close External functions (main)

dvr Interactive Code Compiler

See how the compiler reacts in real-time. Change the access specifier of the goldBars variable inside the BankVault class and observe if main() can access it.

Configuration

Access Specifier for goldBars:

info What's happening?

The variable is public. This means anyone, including the external main() function, can directly read and write to it. It's like leaving the vault door wide open.

main.cpp

class BankVault {
public::
    int goldBars = 100;
};

int main() {
    BankVault myVault;
    
    // Trying to access from outside
    myVault.goldBars = 50;
    return 0;
}

check_circle Build Successful: 'goldBars' is accessible.

account_tree Inheritance & Access

When a class inherits from another class, the access levels can change based on the type of inheritance.

Inheritance Mode:

public inheritance

Public Inheritance: "Is-a" relationship. Public members stay public, protected stay protected.

Test Your Knowledge

1. Which specifier allows members to be accessed by derived classes but NOT by the outside world?

2. In 'class Car : private Vehicle', how do public members of Vehicle appear inside Car?