What is wrong in comparing a null with an object rather than an object with a null

Question

I just found out that I can compare null with an Object like this,

if(null != Object)

Rather than comparing Object with null, like

Object != null

What may go wrong if use the former approach?

Is that legal? If not then why does compiler accept it?

Answer 1

There's one thing wrong about it - readability. If you want to write a clean code, you should care about the way it will be read in the future. It needs to be obvious, what it does and why it does a certain thing. If you place the "Object" to the right of the evaluation, it becomes less apparent what are you really doing. Well at least in my opinion...

Answer 2

Most people say Object != null because it is what they are used to and so it is easier to read.

The best argument I've heard for null != object is to avoid bad expressions. e.g. to pickup a typo in if (var == 1)

if (var = 1) // this is valid C
if (1 = var) // this is not valid C