using static System.Console;

​

namespace DotNetDesignPatternDemos.SOLID.LiskovSubstitutionPrinciple

{

  // using a classic example

  public class Rectangle

  {

    public int Width { get; set; }

    public int Height { get; set; }

​

    public Rectangle()

    {

    }

​

    public Rectangle(int width, int height)

    {

      Width = width;

      Height = height;

    }

​

    public override string ToString()

    {

      return $"{nameof(Width)}: {Width}, {nameof(Height)}: {Height}";

    }

  }

​

  public class Square : Rectangle

  {

        public new int Width

        {

            set { base.Width = base.Height = value; }

        }

​

        public new int Height

        {

            set { base.Width = base.Height = value; }

        }

    }

​

  public class Demo

  {

    static public int Area(Rectangle r) => r.Width * r.Height;

​

    static void Main(string[] args)

    {

      Rectangle rc = new Rectangle(2,3);

      WriteLine($"{rc} has area {Area(rc)}");

​

      // should be able to substitute a base type for a subtype

      /*Square*/ Rectangle sq = new Square();

      sq.Width = 4;

      WriteLine($"{sq} has area {Area(sq)}");

    }

  }

}

​