Setting a type reference type to null doesn't affect copied type?

Question

Why does this produce \"0\" ?

object a = 0;
object b = a;
a = null;
Console.WriteLine(b.ToString()); // Produces \"0\"
Console.Read();

Does

Answer 1

You are setting the reference to null, you are not changing the object the reference points to. a and b are two separate references, hence setting a to null will of course leave b unchanged (Think "pointer"), it just means that a now points to null ("nowhere").