How do C++ operators work

Question

Given that x = 2, y = 1, and z = 0, what will the following statement display?

printf("answer = %d\n", (x || !y && z));

It was on a quiz and I got it wrong, I don't remember my professor covering this, someone enlighten me please... I know the answer I get is 1, but why?

Answer 1

The expression is interpreted as x || (!y &&z)(check out the precedence of the operators ||, ! and &&.

|| is a short-circuiting operator. If the left operand is true (in case of ||) the right side operand need not be evaluated.

In your case x is true, so being a boolean expression the result would be 1.

EDIT.

The order of evaluation of && and || is guaranteed to be from left to right.

Answer 2

If I'm not mistaken, it will print 1. (Let's assume short circuiting is off)

(x || !y && z) or (true || !true && false) will first evaluate the ! operator giving (true || false && false)

Then the &&: (true || false)

Then || : true

Printf will interpret true in decimal as 1. So it will print answer = 1\n