public class LivingBeing
{
    string Name { get; set; }
}
public interface IAnimal 
{
    bool HasHair { get; set; }
}
public interface INoiseMaker
{
    string MakeNoise();
}
//Note that in C#, the base class name must come before the interface names
public class Cat : LivingBeing, IAnimal, INoiseMaker
{
    public Cat() 
    {
        Name = "Cat";
        HasHair = true;
    }
    public bool HasHair { get; set; }
    public string Name { get; set; }
    public string MakeNoise()
    {
        return "Nyan";
    }
}