What is the main idea of encapsulation in object-oriented programming?

Encapsulation is a mechanism that combines data (fields) and methods that work with this data into a single object (class), as well as hiding implementation details from the outside world.

Main ideas:

• Data hiding: The internal state of an object is hidden and accessible only through public methods. This prevents direct modification of data from outside and guarantees its integrity.
• Access control: Access to fields is done through methods (getters and setters), allowing the application of data validation logic when retrieving or modifying data.
• Manageability and support: Changing the internal implementation of a class does not affect code that uses this class if the public interface remains unchanged.

Example:

public class Account {
    private double balance; // Data hiding

    public Account(double initialBalance) {
        if (initialBalance >= 0) {
            this.balance = initialBalance;
        } else {
            this.balance = 0;
        }
    }

    public double getBalance() { // Getter for data access
        return balance;
    }

    public void deposit(double amount) { // Method to modify data
        if (amount > 0) {
            balance += amount;
        }
    }

    public void withdraw(double amount) { // Method to modify data
        if (amount > 0 && amount <= balance) {
            balance -= amount;
        }
    }
}