What is the purpose of null?

Question

I am in a compilers class and we are tasked with creating our own language, from scratch. Currently our dilemma is whether to include a \'null\' type or not. What purpose do

Answer 1

Null is not a mistake. Null means "I don't know yet"

For primitives you don't really need a null (I have to say that strings (in .NET) shouldn't get it IMHO)

But for composite entities it definitely serves a purpose.