Give an example of abstraction in C#.?

Real-World Example: Payment Processing

// Abstract class

abstract class Payment

public abstract void Pay(decimal amount);

public void ShowReceipt(decimal amount) =>

Console.WriteLine($"Paid: {amount:C}");

// Derived classes implement abstraction

class CreditCardPayment : Payment

public override void Pay(decimal amount) =>

Console.WriteLine($"Paid {amount:C} using Credit Card");

class PayPalPayment : Payment

public override void Pay(decimal amount) =>

Console.WriteLine($"Paid {amount:C} using PayPal");

// Usage

Payment payment1 = new CreditCardPayment();

payment1.Pay(500);

payment1.ShowReceipt(500);

Payment payment2 = new PayPalPayment();

payment2.Pay(300);

payment2.ShowReceipt(300);

Explanation:

• Payment defines what a payment should do (abstract method Pay).
• Derived classes (CreditCardPayment, PayPalPayment) define how payment is

made.

• Users interact only with the abstract interface, not the internal logic.

🔹 Section 4: Inheritance – Interview Q&A