SOLID - Open Closed Principle

ocp.cs

//NOT SO GOOD
public class Car
{
   public bool IsBus {get; set;}
   public bool HasTurbo {get; set;}
   public int NumberOfPistons {get; set;}
   public double TotalWeight {get; set;}
   
   abstract public double GetHorsePower(){
      
      if (HasTurbo){
         return TotalWeight / NumberOfPistons + 250
      }else if(IsBus){
          return TotalWeight / NumberOfPistons - 400
      }else{
         return TotalWeight / NumberOfPistons
      }
      //this could get messy fast and we would need to come in and change this class every time we have a new car or calculation
   }
}

//GOOD
abstract class Car
{
   public int NumberOfPistons {get; set;}
   public double TotalWeight {get; set;}
   abstract public double GetHorsePower();
}

//extend abstract base class Car
class MyCar : Car
{
   public int TurboHorsePower {get; set}
   //provide own implementation of GetHorsepower method
   public override double GetHorsePower(){
      return TotalWeight / NumberOfPistons + TurboHorsePower
   }
}