refout.cs

using System;
using System.Collections.Generic;

class Program
{
	public static void Main()
	{
		var la = new B2();
		int ha;
		la.M(out ha);
		la.M(ref ha);
		Console.ReadKey();
	}
	public class B
	{
		public virtual void M(ref int l)
		{
			Console.WriteLine(l);
		}
	}
	public class B1 : B
	{
		public virtual void M(out int l)
		{
			l = 1;
		}
	}
	
	class B2 : B1
	{
		public override void M(ref int l)
		{
			base.M(ref l);
		}
	}
}