What is x+= ?

Question

int x = 0;
x+=3;

It's x + 3? And the x is a result?

Answer 1

It is a shorthand version of:
x = x + 3
So then if x = 1
x = x + 3 equals 4.

Answer 2

it is short hand of x = x + 3
if x = 0 and x = x + 3 then x = 3

Answer 3

Just to add to James answer about increment operators (?), they are ++ and --
If you need to read more about them, you can find information here.

https://en.m.wikipedia.org/wiki/Increment_and_decrement_operators

Answer 4

Just a cautionary note, sometimes the pre and post increment operators can have unexpected results

and what does:

x[i]=i++ + 1;

do

Read here:http://www.angelikalanger.com/Articles/VSJ/SequencePoints/SequencePoints.html

Answer 5

x+=2