Solution Review: Implement Banking Application Using Polymorphism

class Account {
    private double _balance;
    protected double Balance {
        get { return this._balance; }
        // Check before setting the balance
        set { if(value>=0)
              this._balance = value;
            }
    }
    // Constructor
    public Account(double balance) {
        this.Balance = balance;
    }
    //Virtual Methods
    public virtual bool Deposit(double amount) {
        return false;
    }
    public virtual bool Withdraw(double amount) {
        return false;
    }
    public virtual void PrintBalance() {
        Console.WriteLine("The balance is: " + Balance);
    }
}
class SavingsAccount : Account {
    private double _interestRate;
    // Constructor
    public SavingsAccount(double balance)
        : base(balance)
    {   // It's always preferable to initialize fields inside a constructor
        this._interestRate = 0.8;
    }
    // Overridden Methods
    public override bool Deposit(double amount) {
        if(amount > 0) { // Check if amount is non-zero and non-negative
            // Adding to balance with interest rate
            Balance += amount + (amount * this._interestRate);
            return true;
        }
        return false;
    }
    public override bool Withdraw(double amount) {
        if(amount > 0 && amount <= Balance) { // Check if amount is non-zero and less than equal to balance
            // Deducting from balance with interest rate
            Balance -= amount + (amount * this._interestRate);
            return true;
        }
        return false;
    }
    public override void PrintBalance() {
        Console.WriteLine("The saving account balance is: " + base.Balance);
    }
}
class CheckingAccount : Account
{
    // Constructor
    public CheckingAccount(double balance)
        : base(balance) { }
    // Overridden Methods
    public override bool Deposit(double amount) {
        if (amount > 0)
        {
            Balance += amount;
            return true;
        }
        return false;
    }
    public override bool Withdraw(double amount) {
        if (amount > 0 && amount <= Balance)
        {
            Balance -= amount;
            return true;
        }
        return false;
    }
    public override void PrintBalance() {
        Console.WriteLine("The checking account balance is: " + base.Balance);
    }
}
class Demo {
    public static void Main(string[] args) {
        Account SAccount = new SavingsAccount(5000);
        // Creating saving account object
        SAccount.Deposit(1000);
        SAccount.PrintBalance();
        SAccount.Withdraw(3000);
        SAccount.PrintBalance();
        Console.WriteLine();
        // Creating checking account object
        Account CAccount = new CheckingAccount(5000);
        CAccount.Deposit(1000);
        CAccount.PrintBalance();
        CAccount.Withdraw(3000);
        CAccount.PrintBalance();
    }
}