Abstraction vs Encapsulation

Abstraction and encapsulation are related, but they are not the same.

Short Difference

Abstraction  -> hides unnecessary implementation details.
Encapsulation -> protects internal data by controlling access.

Comparison Table

Topic	Abstraction	Encapsulation
Main question	What should the user see?	How should data be protected?
Focus	Interface and essential behavior	Data hiding and validation
Hides	Implementation complexity	Internal state
Achieved by	Public methods, abstract classes, pure virtual functions	Classes, private data, getters/setters, controlled methods
Example	`payment->process()`	`balance` is private and changed through `deposit()`

Example of Encapsulation

class BankAccount {
private:
    double balance;

public:
    void deposit(double amount);
    bool withdraw(double amount);
};

Here, balance is protected from direct access.

Example of Abstraction

class PaymentProcessor {
public:
    virtual ~PaymentProcessor() = default;
    virtual void process(double amount) const = 0;
};

Here, the user only knows the interface process(). The internal payment details are hidden in derived classes.

How They Work Together

Encapsulation often helps build abstraction.

For example, a BankAccount hides its balance using encapsulation. Then it exposes meaningful operations like:

deposit(amount);
withdraw(amount);

Those public methods form an abstraction for using the account.

Viva Answer

Abstraction hides unnecessary implementation details and shows only the essential interface. Encapsulation hides and protects internal data by controlling access. Encapsulation can help implement abstraction, but they are not the same concept.

Quick Check

Which concept hides implementation complexity?
Which concept protects internal state?
Can encapsulation help create abstraction?