dreams.cs

class MyClass ()
{
}

class YourClass ()
{
}

static void Print(MyClass o)
{
    Console.WriteLine ("My class!");
}

static void Print(YourClass o)
{
    Console.WriteLine ("Your class");
{

static void Main ()
{
    MyClass o;
    
    Print (o ?? new YouClass);
}

relaity.cs

class MyClass ()
{
}

class YourClass ()
{
}

static void Print(MyClass o)
{
    Console.WriteLine ("My class!");
}

static void Print(YourClass o)
{
    Console.WriteLine ("Your class");
{

static void Main ()
{
    MyClass o;
    
    if (o == null)
       Print(new YourClass());
    else
       Print (o);
}