How would you design a payment system using abstract classes

nd interfaces?

• Use an interface for common operations: IPayment.
• Use an abstract class for shared behavior like logging.

interface IPayment { void Pay(decimal amount); }

bstract class PaymentBase : IPayment

{
public abstract void Pay(decimal amount);
public void Log(string message) => Console.WriteLine(message);
}
class CreditCardPayment : PaymentBase
{
public override void Pay(decimal amount) =>

Console.WriteLine($"Paid {amount} by Credit Card");

}