what does x— or x++ do here?

Question

it is a silly Q for most of u - i know - but i one of the beginner here, and I can not understand why the output in here are 12 what does this (x--) do to the resu

Answer 1

Example:

x = 7;
y = --x; /* prefix -- */

Here y = 6 (--x reduce x by 1)

y = x--; /* postfix -- */

Here y = 6 (x-- use first the value of x in the expression and then reduce x by 1)