Encapsulation in Practice

Revisiting Properties (Level 1) with real validation, exactly as Java's encapsulation lesson revisited getters/setters:

class BankAccount {
    private double _balance;

    public double Balance {
        get => _balance;
        private set {
            if (value < 0) {
                throw new ArgumentException("Balance cannot be negative");
            }
            _balance = value;
        }
    }

    public void Deposit(double amount) {
        if (amount > 0) {
            Balance += amount;
        }
    }
}

A private set lets outside code read Balance but only this class can change it — enforcing that every change goes through validated methods like Deposit.