Notes

// Base class
public class Vehicle
{
public virtual void StartEngine()
{
Console.WriteLine("Engine started.");
}
}

// Derived class 1
public class Car : Vehicle
{
public override void StartEngine()
{
Console.WriteLine("Car engine started.");
}
}

// Derived class 2
public class Motorcycle : Vehicle
{
public override void StartEngine()
{
Console.WriteLine("Motorcycle engine started.");
}
}

// Example class
public class Example
{
// Method that takes a Vehicle object and calls its StartEngine() method
public void Drive(Vehicle vehicle)
{
vehicle.StartEngine();
}
}

class Program
{
// Main method
static void Main(string[] args)
{
Example example = new Example();
Vehicle vehicle1 = new Vehicle();
Vehicle vehicle2 = new Car();
Vehicle vehicle3 = new Motorcycle();

example.Drive(vehicle1); // Output: "Engine started."
example.Drive(vehicle2); // Output: "Car engine started."
example.Drive(vehicle3); // Output: "Motorcycle engine started."
}
}