How is the following expression evaluated?

[kdeveloper]

Hi all,

Please take a look at the following code snippet.

int x = 0, y = 5, z;

z = x && (y = 10);

The value of y after the evaluation of the above statement is 5.

My question is: Why isn't it 10?

() have a higher precedence than &&, in which case y = 10 should be evaluated before the && operator is.

So according to me the following should have happened
1) y = 10
2) x && y => 0 && 10
3) z = 0
leaving the value of y to be 10

But why is y being 5 after? Why is GCC being weird?

Thank you.

[gerard4143]

Try compiling with the -S switch and see what was assembled...

gcc -S filename

[blinky]

Best guess it's doing a short circuit evaluation because && is a logical operator, probably caused by optimizations. try turning off optimzations.

[gerard4143]

Best guess it's doing a short circuit evaluation because && is a logical operator, probably caused by optimizations. try turning off optimzations.

If you try switching around the terms it works as expected...

(y = 10) && (z = x);

so it probably is a short circuit problem