using System;
public class Program
{
public static void Main()
Bar b = new Bar();
IFoo f = new Bar();
b.PrintMe("b");
b.PrintMe();
f.PrintMe("f");
f.PrintMe();
}
public interface IFoo
void PrintMe(string s = "interface");
public class Bar : IFoo
public void PrintMe(string s = "class")
Console.WriteLine(s);