what's mean x -= y += 9

Question

You can use multiple assignment operators in one line, such as x -= y += 9.

Whether it is equal to x=x-9 &y=y+9 & x-9=y+9 ？？？

Answer 1

x = x-(y+9)
is what i would say

Answer 2

This doesn't exactly answer the question but I have to say it:

You can write it this way but it's bad practice.
Also bad practice is nested ternaries.
Generally when we write code we want to write it in a way that is easily understood.

e.g.
If you look at a well written piece of code 1 year later you can understand what's happening in the code fairly quickly and make the necessary adjustments/corrections/changes.

If you look at a piece of code that's written like a cipher 1 year later I guarantee you that you'll say:
"famp;@ this, ill rewrite the whole thing."

Answer 3

Just great answer by Mbrustler . But remember assignment works different depending the language.

Like in python

x = x + 1
x += 1

Even this have the same result. this two line of codes still works different for python.

Answer 4

Gordie in the last part, x will be assigned to x-y-9 and not x-y+9.
But you cleared that in last 2 lines so it doesn't matter 😄

Answer 5

x-=y+=9 means
x-=(y+=9)
I.e
y=y+9
x=x-y

Answer 6

It means
y=y+9
x=x-y

Answer 7

Breakdown the string by 'equal' sign. You get x=x-y as there is x-=y;
and y=y+9 as there is y+=9

So, substitute and get the final result as follows,
x=x-(y+9).

Answer 8

x = x - y, where y = y + 9