Don't forget that x++ means POSTincrement and ++x means PREincrement. That means before and after, and is usually before or after some execution point. So the equation in some senses (but definitely not all) is equivalent to:

Code:

--y;
z = x - y * b / a;
x++;

This should be a lot easier to evaluate. First y is decremented to -11.

Then z=5 - -11 * 2 / 4

=5 - -22/4

=5 - -5

=5 + 5

=10.

Then x is incremented.