using System;

namespace Articulos.Ch03
{
    public class ClaseBase
    {
        public int X;
        public ClaseBase (int x)
        {
            this.X = x;
        }
    }
    
    public class Subclase : ClaseBase
    {
        // Implementación clase
        
        public static void Main()
        {
            // Produce error CS1729 (Articulos.Ch03.ClaseBase' 
            // does not contain a constructor that takes 0 arguments):
            // ClaseBase cb = new ClaseBase(123);
        }
    }
}