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CSharp · Console

/Program.cs

using System;

class Base
{
	protected int x = 4;
}

class Der:Base
{
	public void foo(Base b)
	{
		Console.WriteLine(b.x);
	}
}

class Sib:Base
{
}
					
public class Program
{
	public static void Main()
	{
		Der d = new Der();
		Sib s = new Sib();
		d.foo(s);
	}
}