Unnamed

using System;

class A
{
public virtual void X(int r=10, bool b=true)
{
Console.WriteLine("r={0}, b={1}", r, b);
}
}

class B: A
{
public override void X(int r=5, bool b=false)
{
Console.WriteLine("r={0}, b={1}", r, b);
}
}

class App
{
static void Main()
{
A a = new B();
a.X();
}
}