Inheritance - abstract

//In Bicycle.cs file
using System;

namespace LearnInheritance
{
  class Bicycle : Vehicle
  {

    public Bicycle(double speed) : base(speed)
    {
      Wheels = 2;
    }

    public override void SpeedUp()
    {
      Speed += 5;

      if (Speed > 15)
      {
        Speed = 15;
      }
    }

    public override void SlowDown()
    {
      Speed -= 5;

      if (Speed < 0)
      {
        Speed = 0;
      }
    }

    //Overriden string method -- use return since there is no void
    public override string Describe()
    {
      return $"This Bicycle is moving on {Wheels} wheels at {Speed} km/h, with license plate {LicensePlate}.";
    }

  }
}
============================================================================================================================
//In Vehicle.cs file
using System;

namespace LearnInheritance
{
  abstract class Vehicle  //label class as abstract so long as it has one abstract method
  {
    public string LicensePlate
    { get; private set; }

    public double Speed
    { get; protected set; }

    public int Wheels
    { get; protected set; }

    public Vehicle(double speed)
    {
      Speed = speed;
      LicensePlate = Tools.GenerateLicensePlate();
    }

    public virtual void SpeedUp()
    {
      Speed += 5;
    }

    public virtual void SlowDown()
    {
      Speed -= 5;
    }

    public void Honk()
    {
      Console.WriteLine("HONK!");
    }

    //abstract method -- has no defailt functionality to inherit like virtual above
    public abstract string Describe();

  }
}
============================================================================================================================
//In Program.cs file
using System;

namespace LearnInheritance
{
  class Program
  {
    static void Main(string[] args)
    {
      Sedan s = new Sedan(60);
      s.SpeedUp();
      Console.WriteLine(s.Describe());

      Truck t = new Truck(45, 500);
      t.SpeedUp();
      Console.WriteLine(t.Describe());

      Bicycle b = new Bicycle(10);
      b.SpeedUp();
      Console.WriteLine(b.Describe());
    }
  }
}