The nullptr and pointer arithmetic

Question

Considering the following code, is it safe to do pointer arithmetic on nullptr?

I assume adding any offsets to a nullptr results in another

Answer 1

is it safe to do pointer arithmetic on nullptr? 

C++ defines two kind of operations on nullptr. For :

float * x=nullptr;
float * y=nullptr;

1. x +/- 0 = x

2. x-y=0 //note x and y have the same type

You cannot make an assumption about what is not defined, so you shouldn't do it.