Studia

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());

            Zienia z = new Zienia() { masa = 100 };
            Mars m = new Mars();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WindowsFormsApplication1
{
    class Zienia: Planeta
    {
        public int masa;

       public override int Masa()
       {
           return masa;
       }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WindowsFormsApplication1
{
    class Mars: Planeta
    {

        public override int Masa()
        { return 0; }
       
    }
}


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WindowsFormsApplication1
{
    abstract class Planeta
    {
       
        public abstract int Masa();
       
    }
}